MODERN ELECTRICAL 

nOTOR CAR 

EQUIPMENT 


ITS PRODUCTION, OPERATION, MAINTENANCE AND REPAIR 



Do you realize that on the Automobile there is a complete Electrical 
Power Plant. The most nearly self-operating, self-sustaining feature of 

THE MODERN MOTOR CAR 


By Thomas E. Countryman, President 

SATISFACTION GARAGE 

Kansas City, Missouri 




Modern Electrical 

MOTOR CAR 

Equipment 


Its Production, Operation, Maintenance 
and Repair 



Copyright 1919, By Thomas E. Countryman 




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OCT 29 ' 9 ' 9 





Contents 


PAGE 

CHAPTER 1; ELECTRICITY ... 7 

What is electricity .-■. T 

CHAPTER 2; MAGNETISM . 7 

General properties of magnets. 7 

The laws of magnetic attraction and repulsion . : . 8 

Magnetic materials ...... 8 

Retentative and permanentability . 9 

Magnetic induction ..:... 8 

Magnetic lines of force . t .- . 9 

Fields of force . 9 

Molecular nature of magnetism .10 

Theory of magnetism . 1’ 

Saturation .-.1 1 

The earth’s magnetism . 11 

CHAPTER 3; MAGNETIC PROPERTIES OF COILS... ..12 

Loops of wire carrying a current equivalent to a magnetic disc .. . 12 

The Helix carrying a current equivalent to a bar magnet .12 

The electro magnet ..... 13- 

CHAPTER 4; CURRENT PRODUCTION . 14 

Current production by chemical action .. 14 

CHAPTER 5; THE OHMS LAW . ...16 

CHAPTER 6; STORAGE BATTERIES. 17 

CHAPTER 7; CONDUCTORS AND INSULATORS . 19 

CHAPTER 8; HOW ELECTRICITY IS TRANSMITTED 20 

CHAPTER 9; FUNDAMENTAL LAWS OF ELECTRICITY .20 

CHAPTER 10; THE PRINCIPLE OF THE DYNAMO AND MOTOR .20 

Currents induced by a magnet ... . . ..20 

CHAPTER 11; DIRECTION OF INDUCED CURRENT.....‘ .......*...20 

The Lenz law .... .20 

Conditions necessary for an induced E M F .,.21 

CHAPTER 12; THE PRINCIPLE OF THE ELECTRIC MOTOR. .21 

The motor^ and dynamo rule . 22r, 

CHAPTER 13; STRENGTH OF THE INDUCED CURRENT OR E M F . 22; 

CHAPTER 14; CIRCUITS INDUCED IN ROTATING COILS.23: 

The dynamo rule . 23 

CHAPTER 15; MECHANICAL GENERATORS OR DYNAMOS .23 

CHAPTER 16; DYNAMOS . 24 

A simple alternating current dynamo ....24 

The multipolar alternator . 24 

The principle of the commutator. 25 

The ring armature direct current dynamo . .25 

The drum armature direct current dynamo .26 

The series shunt and compound wound dynamo. 27 

The construction of a low tension magneto.28- 

Parts of a low tension magneto, shuttle type armature.23 

How Currents are made to alternate in the windings of armature .29 

The inductor type armature magneto ... 

















































CHAPTER 17; THE PRINCIPLE OF THE INDUCTION COIL AND . 

TRANSFORMER .31 

The direction of the induced current .31 

The E M F in the secondary.—....31 

Self induction ...32 

The induction coil .32 

Laminated core Foucault current ..33 

The transformer . 34 

The use of • transformer.....34 

Pressure in the px-imary and secondary...,...34 

'The efficiency of the transformer...34 

CHAPTER 18; ELECTRICAL TRANSMISSION OF POWER.35 

CHAPTER 19; IGNITION SYSTEMS OUTLINED....36 

Timex 1 and distributor forms .36 

The vibrator, its purpose .........36 

The magnetic vibrator . 37 

The mechanical vibrator . 37 

Low tension coil system of ignition.....38 

Purpose of the spark plug..*....39 

CHAPTER 20; THE JUMP SPARK OR HIGH TENSION COIL SYSTEM.40 

The construction of high tension coil system...4‘0 

CHAPTER 21; THE FOUR VIBRATING COIL SYSTEM OF IGNITION 

USED ON THE FORD.....42 

Dual system . 42 

The commutator or timer construction. 42 

How the commutator or timer helps conti’ol the speed .43 

The master vibrator ......44 

CHAPTER 22; THE DISTRIBUTOR OR SYNCHRONOUS SYSTEM 

OF IGNITION .44 

Open and closed circuit principle....-.46 

Electrical lag . 46 

Mechanical lag .46 

The resistant unit ..-----..47 

A thermostat circuit breaker...-.47 

The depolarizing switch .47 

The parts of a modem battexy and coil system of ignition.49 

CHAPTER 23; HIGH TENSION MAGNETOS .52 

' The safety spark gap principle .53 

The safety spark gap’s constnxction... v .53 

1 Timing a magneto within itself .53 

The Bosch NU 4 .._.53 

‘Timing the NU 4 magneto with engine.54 

CHAPTER 24; THE DIXIE HIGH TENSION MAGNETO .54 

The Mason principle on which the Dixie operates..54 

CHAPTER 25; MAGNETO DRIVE METHODS..56 

Means of advancing and retarding of spark.56 

Controlling the spark*. 56 

Magneto speeds . 56 

CHAPTER 26; DRIVING METHODS OF DISTRIBUTOR AND 

TIMER IGNITION SYSTEMS .58 

CHAPTER 27; TIMING THE MAGNETO WITH THE ENGINE .59 

CHAPTER 28; A DIGEST OF TROUBLES AND CAUSES AND REMEDIES 

OF THE IGNITION SYSTEM...60 

CHAPTER 29; LIGHTING THE MOTOR CAR BY ELECTRICITY.63 

CHAPTER 30; CUT-OUT RELAYS.63 






















































f 

f 


I 

\ 

CHAPTER 31; THE AMPERE METER.65 

Mechanical governor .65 

Purpose of ampere meter .65 

The principle and construction of the commercial ammeter and volt meter.65 

CHAPTER 32; REGULATION OF OUTPUT OF GENERATOR.65 

The graphite disc regulation of constant voltage.65 

The therminal principle of control.,...66 

The third brush regulation . 67 

CHAPTER 33; THE ELECTRIC MOTOR...68 

The application of the electric starting motor to the engine.....68 

The mechanical gear shift .1.68 

The electrical automatic gear shift . 70 

The Benedict’s automatic gear shift .— . 69 

CHAPTER 34; FUSES .71 

Multiple switch connections for lighting circuit .72 

The Delco Electric motor generator and ignition unit.74 

CHAPTER 35; COMMUTATOR TROUBLES .74 

CHAPTER 36; ARMATURE TROUBLES . 75 

CHAPTER 37; LOCATING ARMATURE TROUBLES .75 

CHAPTER 38; FIELD WINDING TROUBLES .75 

CHAPTER 39; STORAGE BATTERY POINTERS .'.76 

CHAPTER 40; SUMMARY OF STARTING TROUBLES .77 

CHAPTER 41; CUT-OUT RELAY TROUBLES AND REMEDIES.78 

CHAPTER 42; SHORT CIRCUITS.80 

CHAPTER 43; A DIGEST OF LAMP TROUBLES . !. .81 

CHAPTER 44; THE ELECTRICAL GEAR SHIFT, HOW IT WORKS.82 

The pi’inciple ..83 

Gear changes ............83 

Dropping back . 83 

Selections . 83 

Pre-Selections . 83 

Neutralizing .*.83 

Coasting . 83 

Principle of the solenoid . 83 

CHAPTER 45; THE OWEN-MAGNETIC POWER TRANSMISSION SYSTEM....84 

The elementary principle.84 

Controlling lever system . 84 

Stax-ting current . 84 

Neutral . 85 

First position .85 

Second position .-.85 

Third pisition .85 

Fourth position .85 

Fifth position .85 

High . 85 















































Study Carefully 



POSITIVE TERMINAL OF BATTERY OR GENERATOR 
SOMETIMES ABBREVIATEP"P'' 

— 

GROUND TO 

engine or frame 

— 

NEGATIVE TERMINAL OF BATTERY OR GENERATOR 

SOMETIMES ABBREVIATED "M” 

c 

CARBOFTOF DRY battepy 

z 

ZINC OF DRY battery 

-*T=- 

BATTERY-STORAGE OR DRV CELL 

Hllllfi 

CELLS IN SERIES 

© 

MOTOR - GEJS ERATO F? 
3-TERMINAL 

© 

MOTOR- GENERATOR 
4-TERMINAL 


AMMETER (J 

$ 

VOLTMETER 

P PRIMARY 

© 

SECONDARY 

t© 

GENERATOR 

C@T| MOTOR 


WIRES JOINED TOGETHER, SAME CIRCUIT 

/K- 

WIRES CROSSING; SEPERATE CIRCUITS 

-4mn 

RHEOSTAT OR VARIABLE 
RESISTANCE 

I-®- 11 

SCAN DESCENT LAMP 

-'OTT- 

method of showing AN INDUCTIVE COIL 

4A/W 

METHOD OF SHOWING A NON - INDUCTIVE COIL (ALSO USED TO 

SHOW INDUCTIVE COIL WHEN THERE IS NO OANGER OF CONFUSION) 

gap 

USED for resistance only 

*~0-° AUTOMATIC CUT-OUT 

10 

SHUNT WOUND MACHINE 
MOTOR OR GENERATOR 

(K© SERIES WOUND MACHINE 1 

V > MOTOR OR GENERATOR 

0 

ARMATURE AND BRUSHES OF MOTOR AND GENERATOR 

Hr 

MOTOR BRUSH 
SWITCH 

-4T 

_ SWITCH 

Q Q CONTACT 

P POINTS 

-H 

push button or I 

LIGHTING SWITCH i Cjd*- 

STARTING SWITCH 

® 

PUSH 

BUTTON 

[Q2S30 

“USE 

c&ms&o E 

5 A L L AST 

COIL 

cm 

COWL 

LIGHT 

A/V 

PR1MAF?Y 

COARSE -WIRf 

Wff 

SECONDARY "V 

FINE WIRE J 

30TH IGNITION 

COU 

.{t£5— CON OEMS ER 


HEAVY 

cable 


ARROW INDICATES DIRECTION OF CURRENT PLOW 



✓'MS?"* 

C.W. 

CLOCKWISE REVOLUTION 

^ (counter-clockwise revolution 

V 

VOLT, UNIT OF 

POTENTIAL OR PRESSURE 

A 

AMPERE, UN IT OF CURRENT 

QUANTITY 

DC 

DIRECT CURRENT, FLOWS CONTiNUOULY AND ALWAYS IN ONE DIRECTION 

AC 

ALTERNATING CURRENT; FLOWS FIRST IN ONE DIRECTION 

THEN THE OTHER 

K.W 

K1LOWATT, (1,000 WATT5) 

HP 

HORSE POWER(m watts) 

W 

WATT^ONE VOLT XONE AMPERE 

PP. S P*+enTH\l 

oY Ftpsiky? e\ 

ACUYEPlrt-f 

fc MnE/tc 

TO 

lufiVf Force 


ELECTRICAL SYMBOLS 






































































































MODERN ELECTRICAL 

MOTOR CAR EQUIPMENT 


CHAPTER 1. ELECTRICITY. 

What is Electricity? A great many people have strange ideas of electricity, and 
imagine that a person must be out of the ordinary who can harness up electricity and 
make it do work. Now if you are figuring on analyzing and finding out why electricity 
does certain things, you are on the wrong track. Electricity is the name of a natural 
force that exists everywhere; it is in your body; it is in your clothes; in fact, it is 
everywhere, and the only reason you do not feel a shock is because the electricity is not 
in motion. This electricity that exists everywhere is in the form of magnetism, and is 
at rest and is not noticeable. 

By a great deal of experimenting with electricity men have been able to find out 
how to set it in motion, and harness it up, and utilize it to a great advantage, and it 
has played a very important part in modernizing the automobile. 

CHAPTER 2. MAGNETISM. 

General Properties of Magnets.—It has been known for many centuries that certain 
kinds of ore known as magnetite have the property of attracting small bits of iron and 
steel. This ore probably received its name from the fact that it is especially abundant in 
the Province of Magnesia in Thessaly, although the Latin writer Pliny says that the 
■word Magnet is derived from the name of the Greek Shepherd Magnes who, on the top 
of Mount Ida observed the attraction of a large stone from his iron crook. Pieces of this 
ore which exhibit this attractive property are known as “natural magnets.” It was also 
known to the ancients that artificial magnets may be made by stroking pieces of steel 
with natural magnets, but it was not until about the twelfth century that the discovery 
was made that a suspended magnet will assume a north and south position. Because of 
the latter property natural magnets became known as “load-stones,” or “leading stones,” 
and magnets, either artificial or natural, began to be used for determining direction. 

The first mention of the use of the compass in Europe is in 1190; it is thought to 
have been introduced from China. Magnets are now made by either stroking bars of steel 

in one direction with a magnet, or by passing electric cur¬ 
rents about the ba.r in a manner to be described later. The 
form shown in Diagram 1 is called a “bar magnet.” That 
shown in Diagram 2 is a horseshoe magnet. The horse¬ 
shoe magnet form is the more common. If a magnet is 
dipped into iron filings, the filings will be seen to cling in 
a tuft near the end, but scarcely at all near the middle, 
as shown in Diagram 3. 

These places near the end of a magnet, at which its 
strength seems to be concentrated, are called the “poles of 
the magnet.” The end of a freely swinging magnet which 
points to the north is designated as the north seeking, or 
simply the north pole (N), and the other end as the south 
seeking or. the “south pole” (S). The direction in which a 
compass needle points is called the “magnetic meridian.” 


l» r. m 

Diag.'i a bar magnet 



Disg 4 3 Iron filings cling¬ 
ing to bar magnet 









8 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 



Diag.4 Magnetic at¬ 
tractions and repulsions 


The Law of Magnetic Attraction and Repulsion.—In the experiment with the iron 
filings no particular difference was observed between the action of the two poles. That 

there is a difference, however, may be shown by experiment¬ 
ing with two magnets, eithei of which may be suspended as 
shown in Diagram 4. If two north poles are brought near 
one another they are found to repel each other. The south 
poles likewise, are found to repel each other, but the north 
pole of one magnet is found to be attracted by the south pole 
of another. The results of these experiments may be sum¬ 
marized in a general law. MAGNETIC POLES OF LIKE 
KIND REPEL EACH OTHER, WHILE POLES OF UNLIKE 
KIND ATTRACT EACH OTHER. 

The force which any two poles exert upon each other has 
been found, like the force of gravitation, to vary inversely as 
the square of the distance between them. A unit pole is de¬ 
fined as a “pole” when placed at a distance of one centimeter from an exactly similar 
pole will repel it with a force of a dyne, which, acting upon a gram per second, generates 
a velocity of one centimeter. 

Magnetic Materials.—Iron and steel are the only substances which exhibit magnetic 
properties to any marked degree. Nickel and cobalt are also attracted appreciably by 
strong magnets. Bismuth and antimony substance are actually repelled instead of 
attracted, but tyre effects are very small. Recently it has been found possible to make 
quite strongly magnetic alloys out of certain nonmagnetic materials. For example, a 
mixture of 65% copper, 27% manganese, and 8% aluminum is quite strongly magnetic. 
These are called “hesular alloy.” For practical purposes, however, iron and steel may 
be considered as the only magnetic materials. 

Magnetic Induction.—If a small unmagnetized nail is suspended from one end of a 
bar magnet, it is found that a second nail may be suspended from this first nail which, 
itself, acts like a magnet. A third from the second, etc., ard so 
on, as shown in Diagram 5; but if the bar magnet is carefully 
pulled away from the first nail, the others will instantly fall 
away from each other, thus showing that the nails were strong 
magnets only so long as they were in contact with the bar 
magnet. Any piece of soft iron may be thus magnetized tempo¬ 
rarily by holding it in contact^with a permanent magnet; indeed, 
it is not necessary that there be actual contact, for if a nail is g 

simply brought near the permanent magnet, it is found to be- Magnetism 

come a magnet. This may be proved by presenting some iron induced by contact 

filings to one end of a nail, held near a magnet in the manner 
-ip shown in Diagram 6. Even inserting a plate of glass, or of 

copper, or any other material except iron between the north and 
south will not change appreciably the number of filings which 
cling to the end of the south pole of the nail. This shows the 
fact that nonmagnetic materials are transparent to magnetic 
forces, but as soon as the permanent magnet is removed, most of 
the filings will fall. Magnetism produced in this way, by the 
mere presence of adjacent magnets, with or without contact, is 
called induced magnetism. If the induced magnetism of the nail 
in Diagram 6 is tested with a compass needle it is found that the 
remote or the farthest away pole of the nail is of the same kind 
as the inducing pole, while'the near pole is of unlike kind. This is the general law of 
magnetic induction. 

Magnetic induction explains the fact that a magnet attracts an unmagnetized piece 
of ii’on, for it first magnetizes it by induction, so that the near pole is unlike the inducing 



Diag.6 

Magnet¬ 
ism induced with 
out contact 

















MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


9 


pole, and the remote pole like the inducing pole, and then since two unlike poles are 
closer together than the like poles, the attraction overbalances the repulsion, and the 
iron is drawn towards the magnet. Magnetic induction also explains the formation of 
the tufts of iron filings shown in Diagram 3. Each little filing becomes a temporary 
magnet, such that the end which points towards the inducing pole is unlike this 
pole, and the end which points away from it is like this pole. The brushlike appearance 
is due to the repulsive action which the outside free poles exert upon each other. 

Retentive and Permeability.—A piece of soft iron will very easily become a 
strong temporary magnet, but when removed from the influence of the magnet, it 
loses practically all of its magnetism. On the other hand, a piece of steel will not be 
so strongly magnetized as soft iron, but it will retain a much larger fraction of its 
magnetism after it is removed from the influence of the permanent field. This power 
of resisting either magnetization or demagnetization is called “retentivity.” Thus steel 
has a much greater retentivity than wrought iron, and in general, the harder the steel 
the greater its retentivity. A substance which has the property of becoming strongly 
magnetic under the influence of a permanent magnet, whether it has a high retentivity 
or not, is said to possess permanent ability in large degrees; thus iron is much more 
permeable than nickel. 

Magnetic Lines of Force.—If we could separate the north and south poles of a small 
magnet so as to get an independent north pole, and were to place this north pole near 
the north pole of a bar magnet it would move over to the south pole along some curved 

path similar to that shown in Diagram 7. The 
reason it would move in a curved path is that it 
would be simultaneously compelled by the north pole 
on the bar magnet, and attracted by its south pole, 
and the relative strength of these two forces would 
continually change, as the relative distance of the 
moving poles from these two poles change. To verify 
this conclusion let a strongly magnetized sewing 
needle be floated in a small cork in a shallow dish of 
water, and let a bar or horseshoe magnet be placed 
just above or just beneath the dish, as shown in 
Diagram 8. The cork and needle will then move as 
would an independent pole, since the remote pole of 
the needle is so much farther from the magnet than 
the near pole its influence of the motion is very small. 
The cork will actually be found to move in a curved 
path from north to south. Any path which an inde¬ 
pendent north pole would take in going from north to south is called a line of force. The 
simplest way of finding the direction of this path at any point near a magnet is to hold 
a short compass needle at the point considered. The compass needle sets itself along 
the lines in which its pole would move if independent, that is, along the lines of force 
which pass through the given point, as illustrated in Diagram 7. 

Fields of Force.—The region about a magnet in which its magnetic force can be 
detected is called its field of force. The easiest way of gaining an idea of the way in 
which the lines of force are arranged in the magnetic field about any magnet is to sift 
iron filings upon a piece of paper placed immediately over the magnet. Each little 
filing becomes a temporary magnet by induction, and therefore, like the compass needle, 
sets itself in the direction of the line of force at the point where it is. 

Diagram 9 shows how the filings arrange themselves about a bar magnet; Diagram 



Dirg. £ 7 A line of 
force set up by the 
Magnet A B 



Diag 

* G' Showing direction of a 
motion of an isolated pole near 


magnet 













10 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


10 is the corresponding ideal diagram showimg 
the Hnes of force emerging from the north pol« 
and passing about in curved paths to the south 
pole. It is customary to imagine these lines 
as returning through the magnet from south to 
north, in the manner shown, so that each line 
is thought of as a closed curve. This idea was 
introduced by Faraday and has been found of 
great assistance in correlating the facts of 
magnetism. A magnetic field of unit strength 
is defined as a field in which a unit magnetic 
pole experiences one dyne of force. It is 
customary to represent geographically such a 
field by drawing one line per square centi¬ 
meter through a surface such as A, B, C, D, as 
shown in Diagram 11 taken at right angles to 
the line of force. If a unit north pole between 
north and south were pushed away towards 
south pole with a force of one thousand dynes, 
the strength of the field would be one thousand 
units, and fc it would be represented by one 
thousand lines per square centimeter. 



Ideal diagram of field 
of a bar magnet 



Di ag o 9 Arrangement of iron' 
filings about a bar magnet 



Jl&g «1Thg strength of a mag¬ 
netic field is represented by the 
inumber of lines of force per square 
centimeter 


Molecular Nature of Magnetism.—If a small 
test tube full of iron filings be stroked from one 
end to the other with a magnet it will be found 
to have become itself a magnet, but it will lose 
its magnetism as soon as the filings are shaken 
up. If a magnetized knitting needle is heated 
red hot_ it will be found to have lost its mag¬ 
netism completely. Again, if such a needle is 
jarred or hammered or twisted, the strength of 
its poles as measured by their ability to pick 
up tacks or iron filings will be found to be 
greatly diminished. These facts point to the 
conclusion that magnetism has something to do 
with the arrangement of the molecules, since 
causes which violently disturb the molecules of 
a magnet weaken its magnetism. Again, if a 
magnetized needle is broken each part will be 



& JV 

^ tr n—I- ^ 


found to be a complete magnet; that is, two 
new poles will appear at the points of the 
breaking. A new north pole on the part which 
was the original south pole; and a new south 
pole on the part which was the original north 
pole. The subdivision may be continued in¬ 
definitely, but always the same results as indi¬ 
cated in Diagram 12. This suggests that the 
molecules of a magnetized bar may themselves 
be little magnets arranged in rows with their 

opposite poles in contact with each other. If an unmagnetized piece of hard steel is 
pounded vigorously while it lies between the poles of a magnet, or if it is heated to 
redness and then allowed to cool in this position, it will be found to have become 
magnetized. This suggests that the molecules of the steel are magnetized, even when 
the bar as a whole is not magnetized, and that magnetization may consist in causing 


Diag e 12 Effect of breaking a magnet 























MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


11 


them to arrange themselves in rows, end to end, just as the magnetization of the tube 
of iron filings mentioned above was due to a special arrangement of the filings. 


^ USD ^ BID \ | C$j, ^ OB Cgj, OB,^ ^ 

<? I % 

\ ama^c^^ %,<& § *55 <P % % Hum 

Diag« 13 Arrangement of molecules in an 
unmagnetized iron bar 


outside magnetic force into some such 
arrangement as that shown in Diagram 
14, in which the opposite poles completely 
neutralize each other except in the mid¬ 
dle of the bar. According to this view, 
heating and jarring weaken magnets be¬ 
cause they tend to shake the molecules 
out of alignment. On the other hand, 
heating and jarring facilitate magnetiza¬ 
tion when the bar is between the poles of 
a magnet, because they assist the mag- 


i oms aa on as cm am cm cbb a® am ass cn cm cub am oh a® 

| cjs an cb an cot an cm mu cm an am cm on cnS cub an an 
an am on as aa cm cot cm os cm oh cm na cm on am cm 

j Ol CBB OE OB Oil COT C3E COT PM OH OB OB OB DB OD OB OB 

D i £g ,15 Arrangement of molecules in a 
saturated magnet 

recentivity than soft iron because its mo 
once they have been aligned. 


Theory of Magnetism.—In an un¬ 
magnetized bar of iron or steel it is 
probable then that the molecules them¬ 
selves are tiny magnets which are ar¬ 
ranged either haphazard or in little 
closed groups or chains as in Diagram 
13, so that on the whole opposite poles 
neutralize each other throughout the bar, 
but when the bar is brought near a mag¬ 
net the molecules are swung around by the 


f> \ $ $ % 

\ 6Asss2«d«o innn \ \ 

Diag.U Arrangement of molecules in a 
magnetized iron bar 


netizing force in breaking up the mole¬ 
cule groups and chains, and getting the 
molecules into alignment. Soft iron has 
higher permeability than hard steel, 
because the molecules of the former sub¬ 
stance are much easier to swing into 
alignment than those of the latter sub¬ 
stance. Steel has a very much greater 
es are not easily moved out of position 


Saturation.—Strong evidence of the correctness of the above view is found in the 
fact that a piece of iron or steel cannot be magnetized beyond a certain limit, no matter 
how strong is the magnetizing force. This limit probably corresponds to the condition 
in which the axis of all the molecules are brought into parallelism, as in Diagram 15. 
The magnet is then said to be saturated, since it is as strong as it is possible to make it. 


Earth Magnetism.—The fact that a compass needle always points north and south, 
or approximately so, indicates that the earth itself is a great magnet, having a south pole 
near the geographical north pole, and a north pole near the geographical south pole, for 
the magnetic pole of the earth which is near the geographical north pole must, of course, 
be unlike the pole of a suspended magnet which points towards it, and the pole of the 
suspended magnet which points towards the north is the one which, by convention, it 
has been decided to call the north pole. 














12 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


CHAPTER 3. MAGNETIC PROPERTIES OF COILS 

Loops of Wire Carrying a Current Equivalent to a Magnet Disc.—Let a single loop 
of wire be suspended from a thread in the manner shown in Diagram 16, so that its ends 

dip into two mercury cups, then let the current from three or 
four dry cells be sent through the loops; the latter will be found 
to slowly set itself so that the face of the loops from which the 
magnetic lines emerge is towards the north. Let a bar magnet 
be brought near the loop, the latter will be found to behave to¬ 
wards the magnet in all respects as though it were a flat mag¬ 
netic disc whose boundary is the wire, the face which turns to¬ 
wards the north being a north pole, and the other a south pole 
as illustrated in Diagram 17. 

The experiment shows what 
position a loop carrying a 
current will always tend to 
assume in a magnetic field, 



for since a magnet tends to 
set itself so that the lines 
connecting its pole are paral- 


Diag.16 A loop 
equivalent to a flat 
magnetic disk 

iel to the direction of the magnetic line of the field 
in which it is placed, a loop must set itself so that 
ft line connecting its magnetic pole is parallel to the 
lines of a magnetic field; that is, so that the plane of 
the loop is perpendicular to the field. (See Diagram 
18), or to state the same thing in slightly different 
form, if a loop of wire free to turn is carrying a cur¬ 
rent in a magnetic field, the loop will set itself so as 
to include as many as possible of the lines of force of the field. 



Difig • 17 North pole of disk 
is face from which magnetic 
lines emerge ; south face is 
face into which they enter 



Diagram 18. Posi¬ 
tion assumed by a 
loop carrying a cur¬ 
rent in a magnetic 

field. 


The Helix Carrying a Current Equivalent to a Bar Mag¬ 
net.—Let a wire bearing a current be wound in the form of a 
Helix and held near a suspended magnet as in Diagram 19, it 
will be found to act in every respect like a magnet with a 
north pole at one end and a south pole at the other. This 
result might have been predicted from the fact that a single 
loop is equivalent to a flat disc magnet, for when a series of 
such discs is placed side by side as in the Helix the results 
must be the same as placing a series of disc magnets in a 
row; the north pole of one being directly in contact with the 
south pole of the next. These poles would therefore all neu¬ 
tralize each other excepting at the two ends. We therefore 
get a magnetic field of the shape shown in Diagram 20, the 
direction of the arrows representing as usual the direction in 
which a north pole tends to move. The right hand rule, as 
illustrated in Diagram 21 is sufficient in every case to de¬ 
termine which is the north and which is the south pole of a 


Helix; that is, from which end the lines of mag¬ 
netic force merge, and at which end they enter it. 
The law is thus: if the coil is grasped in the right 
hand in such a way that the fingers point in the 
direction in which the current is flowing in the 
wires, the thumb will point in the direction of the 
north pole of the Helix as illustrated in Diagram 
21. Similarly if the sign of the pole is known, but 



helix 


























MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


13 



piag.20 Magnetic field of helix 


the direction of the current unknown, it may be 
determined as follows: if the right hand is 
placed against the coil with the thumb point¬ 
ing towards the north pole of the Helix, the 
fingers will pass around the coil in the di¬ 
rection in which the current is flowing. 

The Electromagnet.—Let a core of soft 
iron be inserted in the Helix as shown in Dia¬ 
gram 22, the poles will be found to be enor¬ 
mously stronger than before; this is because 
the core is magnetized by induction from the 
field of the Helix in precisely the same way in 
which it would be magnetized by induction, if 
placed in the field of a permanent magnet. The 
new field strength about the coil is now the sum 
of the fields due to the core, and that due to the 
coil. If the current is broken the core will at once 
lose the greater part of its magnetism; if the cur¬ 
rent is reversed, the polarity of the core will be 
reversed. Such a coil with a soft iron core is 
called an “electromagnet.” The strength of an 
electromagnet can be very greatly increased by 
giving it such form that the magnetic lines can 
remain in soft iron throughout their entire length 

instead of emerging into air as they do in Dia- 
gram 22. For this reason the electromagnets are 
usually built in the horseshoe form and provided 
with an armature, A, shown in Diagram 23, 
through which a complete iron path for the lines 
of force is established as shown in Diagram 24. 
The strength of such a magnet depends chiefly 
upon the number of ampere turns which encircle 
it. The expression, “ampere turns,” denoting the 
product of the number of turns of wire about the 
magnet by the number 
each turn; thus a cur- 
rent of one hundredth 
of amperes flowing in 
ampere flowing one 
thousand times around 
a core will make an 
electromagnet of pre¬ 
cisely the same strength 
as a current of one am¬ 
pere flowing ten times 
about the coil. 






Diag.22 The bar electr 
magnet 


ro- 




JA 


Di£.£*23 “The horseshoe 
electromagnet 


Diag*24 Magnetic 

circuit of an electro¬ 
magnet 




























































u 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


CHAPTER 4. CURRENT PRODUCTION. 


ExternaI Circuit 



Da&g $ 25 Shows prin¬ 
ciple of current pro¬ 
duction hy chemical 
action 


Current Production by Chemical Action.— 

The simplest method of current generation is 
by various forms of chemical current producers 
which may be either primary or secondary in 
character. A. simple form of cell is shown in 
section in Diagram 25, and as the action of all 
devices of this character is based on the same 
principle, it will be well to consider the methods 
of producing electricity by the chemical action 
of a fluid upon the metal The simplest cells 
shown consist of a container which is filled with 
an electrolyte which may be either an alkali or 
an acid solution; immersed in the liquid are 
two plates of metai, one being of copper, the 
other zinc. A wire is attached to each plate by 
means of a suitable screw terminal. If the 
ends of the plates which are not immersed in 
the solution are joined together a chemical 
action will take place between the electrolyte 
and the zinc plate; in fact, any form of cell 
consists of dissimilar elements which are capa¬ 
ble of conducting electricity immersed in a 


Carbon Rod 


Terminal 


Terminal 


liquid which will act on one of them more than 
on the other. The chemical action of the elec¬ 
trolyte on the zinc libeiates gas bubbles which 
are charged with electricity and which deposit 
themselves on the copper plate. The copper 
element serves merely as a collecting member 
and is termed the positive plate, while the zinc, 
which is acted upon by the solution, is termed 
the negative plate. The flow of the current is 
from the zinc to the copper plate through the 
electrolyte, and it is returned from the copper 
plate to the zinc element by the wires which 
comprise the external circuit. While in the cell 
shown at Diagram 25 zinc and copper are used, 
any other combinations of metals, between 
which tnere exists a difference in electrical con¬ 
ditions when one of them is acted upon by a 
salt or acid, may be employed. Any salt or 
acid solution will act as an electrolyte if it will 
combine chemically with one of the elements, 
and if it does not at the same time offer too 

great a resistance to the passage of the electric current. The current strength will vary 
with the nature of the elements used, and will have a higher value when the chemical 
action is greater between the negative member and the electrolyte. 

As the vibration which obtains when the automobile is driven over highways makes 
it difficult to use cells in which there is a surplus of liquid, a form of cell has been devised 
in which the liquid electrolyte is replaced by a solid substance which cannot splash out of 
the container even if the cell is not carefully sealed. A current producer of this nature 
is shown in section at Diagram 26. This is known as a dry cell and consists of a zinc 
■can in the center of which a carbon rod is placed. The electrolyte is held close to the 


Depolarizer- 



Diag, 4 26 j)ry 


osorb 

ent 

Lining 


Ce 13 





































MODERN ELBCTRICAL MOTOR CAR EQUIPMENT 


1 # 

ainc or negative member by an absorbent lining of blotting paper, and the carbon rod 
is surrounded by some depolarising material, the top of the cell is sealed with pitch 
to prevent loss of the depolarizer. The depolarizer is needed that the cell may continue 
to generate current when the circuit of a simple cell is completed. The current genera¬ 
tion is brisker at first than after the cell has been producing electricity for a time. While 
the cell has been in action the positive element becomes covered with bubbles of hydrogen 
gas which is a poor conductor of electricity, and tends to decrease the current output of 
the cell. To prevent these bubbles from interfering with current generation some means 
must be provided for disposing of the gas; in dry cells the hydrogen gas that causes 
polarization is combined with oxygen gas evolved by the depolarizing medium, and the 
combination of these two gases produces water which does not interfere with the action 
of the cell. Carbon is used in the dry cell instead of copper, because it is a cheaper 
material, and the electrolyte is a mixture of salammoniac and chloride of zinc which is 
held in intimate contact with the zinc shell which forms the negative element by the 
blotting paper liner. A single dry cell will not produce sufficient current when properly 
transformed or stepped up to ignite the charge of gas in the engine cylinders; there¬ 
fore it is a common practice to combine two or more cells in such a manner that batteries 
are formed which will give more current than a single cell. If it is desired to increase 
the voltage, the cells are combined in series as shown in Diagram 27. If one dry cell 



pXSg.27 ^-Methods of Joining Dry Cells to Form Batteries of Varying Value. 

will produce one and one half volts, and six volts are needed to produce the spark in 
the engine cylinders, the current value of one dry cell is increased by coupling three 
others to it in a series connection. When cells are connected in series, it is the unlike 
elements which are joined together. For example, the zinc of one cell should be join<ed 
with the carbon of the adjacent member by a flexible conductor; this will leave the carbon 
of one end cell and the zinc of the other end cell free, so that they can be joined to the 
apparatus in the outer circuit. When it is desired to obtain more amperage or current 
quantity than could be obtained from a single cell, they are joined in series multiple as 









16 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


also shown in Diagram 27. With this method of wiring, two or more sets of four cells 
which have been joined in series are used; the zinc of one set is joined with the 
zinc elements of the others, and the two carbons are similarly connected. Any number 
-of sets of cells may be connected in series multiple, and the amperage of the combination 
is increased proportionately to the number of sets joined together in this manner. When 
dry cells are connected in series, the voltage of one cell is multiplied by the number of 
cells, and the amperage obtained to the set is equal to that of one cell. When connected 
in series multiple the amperage is equal to two cells and the voltage production produced 
is equivalent to that obtained from four cells. When twelve cells are joined in series 
multiple, as shown in Diagram 27, the amperage is equal to that of one cell multiplied 
by three, while the voltage or current pressure is equal to that produced by one cell 
multiplied by the number of cells which are in series in any one set. By properly com¬ 
bining dry cells in this manner, batteries of any desired current strength may be obtained. 
The term volt and ampere are merely units by which current strength is gauged. The 
•volt is a unit of pressure or potential which exists between the terminals of a circuit. 
The ampere measures current quantities or flow, and is independent of the pressure. 
One may have a current of high amperage at low voltage, or one having great pres¬ 
sure but little amperage or current strength. Voltage is necessary to overcome 
resistance, while the amperage available determines the heating value of the current. 

CHAPTER 5. THE OHMS LAW. 

One volt will force a current of electricity through one ohm of resistance at the rate 
of one ampere per hour. 

Volts divided by ohms equals amperes. 

Volts divided by amperes equal ohms. 

, Amperes times ohms equals volts. 

Example: 110 volts, 56 ohms equals two amperes. The amount passing in one 
hour volts times amperes equals watts, and 1000 watts a kilowatt. 

As the resistance to current flow increases'the voltage must increase proportionately 
to overcome it. A current having the strength of one ampere with the pressure of one 
volt is said to have a value of one watt, which is the unit by which the capacity of a 
generator and amount of current consumption is gauged. One of the disadvantages 
of primary cells, as those types which utilize zinc as a negative element, is 
that the chemical action produces deterioration and waste of material by oxidation. 
Dry cells are usually proportioned so that the electrolyte and depolarizing material 
become weaker as the zinc is used, and when a dry cell is exhausted it is not profitable 
to attempt to recharge it, because new ones can be obtained at a lower cost than the 
-expense of renewing the worn elements. The number of dry cells necessary will vary 
with the system of ignition employed and the size of the motor—while two or three 
cells will ignite small engines such as are used in motorcycles and small stationary 
engines, five or six will be needed on automobile engines employing high tension 
ignition. When the make and break system, or low tension method is used, eight or 
ten cells are necessary. If the engine is a multiple cylinder one, it will draw more 
current than a single cylinder type, because of the greater frequency of spark. On four 
cylinder cars dry cells should be joined in multiple series, which is the most economical 
arrangement. Cells used in multiple connections are more enduring than if the same 
number were used independently in single series connection. A disadvantage of a dry 
cell battery is that it is suited only for intermittent service and it will soon become 
exhausted if used where the current demands are severe; for this reason most automo¬ 
biles in which batteries are used for ignition, employ storage or secondary batteries to 
furnish current regularly, and a set of dry cells is provided for use only in case of 
emergency when the storage battery becomes exhausted. 



MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


17 


CHAPTER 6. STORAGE BATTERIES. 

Let two six by eight inch lead plates be screwed 
to a half inch strip of some insulating material as in 
Diagram 28 and immersed in a solution consisting of 
one part of sulphuric acid to ten parts of water. Let 
a current from two storage or three dry cells in 
series C be sent through this arrangement and 
ammeter A or any low resistant galvometer being 
inserted in the circuit as the current flows, 
hydrogen bubbles will be seen to rise from the 
negative plate at which the current leaves the solu¬ 
tion while the positive plate will begin to turn dark 
brown; at the same time the reading of the ammeter will be found to decrease rapidly. 
The brown coating is • a compound of lead and oxygen called lead peroxide, which 
is formed by the action upon the plate by the oxygen which is liberated by the chemical 
action. Let now the battery be removed from the circuit by opening the key K1 and 
let an electric bell be inserted in their place by closing the'key K2; the bell will ring, 
and the ammeter A will indicate a current flowing' in a direction opposite to that of 
the original current. This current will decrease rapidly as the energy which was stored 
in the cell by the original current is expended in ringing the bell. This experiment 
illustrates the principle of the storage battery. Properly speaking, there has been no 
storage of electricity, but only a storage of chemical energy. Two similar lead plates 
have been changed by the action of the current into two dissimilar plates, one of lead 
and lead peroxide; for any two dissimilar metals in an electrolyte constitutes a primary 
cell; in this case the lead peroxide corresponds to the copper of an ordinary cell and the 
lead plate to the zinc. The cell tends to create a current opposite the direction to that 
of the charging current; that is, its E M F pushes back against the E M F of the charg¬ 
ing cell. It was for this reason that the ammeter reading fell when the charging current 
was removed. This cell acts exactly like the primary cell shown at Diagram 25, and 
furnishes a current until the thin coating of peroxide is used upf or when the cell is: 
exhausted, the plates return to their metallic condition, and are practically the same,, 
and as there is but little difference in the electrical conditions existing between them: 
they do not deliver any current until the electricity has been passed through the cell 
so as to change the lead plate to oxide of lead instead of metallic lead. The only 

important difference between a commercial storage cell,,. 
Diagram 29, and the one shown in Diagram 28 is that 
means are provided in the making with a much thicker coat 
of the active material, lead peroxide on the positive plate 
and a porous, spongy lead on the negative, than can be 
formed by a single charge such as we used in Diagram 28. 
This material is pressed into interstices in the plates ar 
shown in Diagram 29. The E M F of the storage cell is: 
about 2.2 volts. Since the plates are always very close 1 
together and may be given any desired size, the internal’ 
resistance is usually small, so that the current furnished' 1 
may be very large. The usual efficiency of the storage celf 
is about 75%; that is, only about three fourths as muclv 
electrical energy can be obtained from it as is put into it... 
When storage cells are to be used in automobile work they - 
are combined in a single container as shown at Diagram 30. 
which is a part section of a commercial storage battery. 
The main containing member, a jar of hard rubber, is.- 
divided into three parts. Each of these compartments serve to hold the elements com¬ 
prising one cell; the positive and negative plates are spaced apart by wood and hare. 



Plate Storage 

Cell 



Diag.26 rhe principle oi 
the storage battery 































^_ modern electrical motor car equipmen t. 

rubber separators which prevent short circuiting between the plates. After the ele¬ 
ments have been put in place in the compartaients forming the individual cells of the 
battery, the top of the jar is sealed by pouring a compound of pitch and rosin or asphalt 
over the plates of hard rubber, which keep the sealing material from running into the 



Diag. * 30 A three cell 
Storage Battery 


cells and onto the plates. Vents are provided over each cell through which gases 
produced by charging or discharging are allowed to escape. These are so formed that 
while free passage of gas is provided for, it is not possible for the electrolyte to splash 
out when the vehicle is in motion. It will be evident that this method of sealing would 
not be practical on a cell where the members attacked by the acid have to be replaced 
from time to time, but in a storage battery only the electrolyte needs to be removed. 
"When the plates are discharged they are regenerated by the passing of a current of 
electricity through them; new electrolyte can be easily inserted through caps in which 
the vents are screwed. The cells, of which a storage battery is composed, are joined to¬ 
gether at the factory with bars of lead which are burned in place, and only two free 
terminals are provided by which the battery is coupled to the outer circuit. The 
capacity of a storage battery depends upon the size and the number of plates per set, 
while the potential or voltage is determined by the number of cells joined in series from 
the battery. Each cell has a difference of potential of two and two tenths volts when 
fully charged; therefore, a two-cell battery will deliver a current of 4.4 volts, and a 
three cell type as shown at Diagram 30 will give about 6.6 volts, between the terminals. 
Diagram 30 shows each cell as composed of four plates and their separators; two of the 
plates are positive, the remaining two negative members; the size of storage battery to 
be used depends upon the number of cylinders of the engine or the specific kind of work 
it is called upon to do. Four cylinder motors usually take a 6 volt, 60 ampere hour 
battery, but it is desirable to supply a 6 volt battery having 80 ampere hour capacity for 
six cylinder motors. 












































MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


19 

To-day in modern automobile construction the storage battery performs a very im¬ 
portant job in the starting and lighting and ignition systems; therefore it is very im¬ 
portant for one who wishes to understand the electrical systems of the automobile to 
thoroughly understand how electrical currents are produced by the chemical generator. 

CHAPTER 7. CONDUCTORS AND INSULATORS. 

The Transference of Heat, or Conduction in Solids.—If one end of a short metal bar 
be held in the fire the other end soon becomes too hot to hold; but if the metal rod 
is replaced by one of wood or glass, the end away from the flame will not be appreciably 
heated. This experiment and others like it show that nonmetallic substances possess a 
much smaller ability to conduct heat than do metallic substances; but, although all 
metals are good conductors as compared with nonmetals, they differ widely among them¬ 
selves in their conducting powers. Let copper, iron, and German silver wire, twelve inches 
long, and about one eighth inch in diameter be twisted together at one end, as in Diagram 
31, and let a Bunsen flame be applied to the twisted ends. Let a match be slid slowly 
from the cool end of each wire towards the hot end until the heat from the wire ignites 
it; the copper will be found to be the best conductor, and the German silver the poorest. 

How Electricity is Transmitted.—Electricity produced 
in one place may be transmitted to another place provided 
a path is arranged so that it may return to where it started 
from. It will not flow if there is no circuit, that is, a con¬ 
tinuous path. If the circuit is broken, the flow will im¬ 
mediately stop, and will not start again until the circuit 
is once more completed. Copper wire is usually used to 
take the electric current from where it is produced to the 
place where it is to be used, and another wire may be used 
to bring it back again. The first wire being called the 
lead and the second the return. If there is any way in 
which the current may leak from the lead wire and return 
to the starting point without going through the entire 
circuit, it will do so, and this leakage is called a “short 
circuit.” Anything that will permit a current of electricity to pass through it is called 
a “conductor.” All metals are conductors. Substances such as rubber, china, porcelain, 
glass, wood fiber, and mica are called nonconductors, or insulators. A wire is insulated 
to prevent the current of electricity from escaping by wrapping it with cotton or silk, 
which is soaked with rubber to prevent dampness from getting in. 'When dry, cotton and 
silk are insulators; but as water is a conductor, damp cotton and silk cease to be 
insulators. Water, dampness, and oil are good conductors of high voltage currents, but 
are poor conductors under one hundred volts. While all metals are conductors, some are.' 
better than others. A copper wire, for instance, will pass a larger current than an 
iron wire of the same size, due to the fact that copper has a lower resistance. If a wire. 1 
has more electricity passed through it than it can easily conduct, heat may be generated,, 
and it will get so hot it will melt. The larger a wire is the larger the current that it 
can pass without heating. Copper is in most general use as a conductor of electricity 
because it will permit larger currents to pass than almost any other metal. Silver 
is a better conductor, but cannot be used because of the expense. 

» / 



Diag.51 Differences in 
heat conductivities of 
metals 


I 









MODERN ELECTRICAL MOTOR CAR EQUIPMENT 




CHAPTER 9. FUNDAMENTAL LAWS OF ELECTRICITY. 

These should be mastered by anyone who contemplates becoming an electriaian or 
an ignition man. 

1st; A current of electricity must always have a complete circuit. 

2d; You have always got a complete circuit as long as the voltage or pressure ia 
high enough to force the current through the resistance. 

3d; A current of electricity must always return to its starting place. 

4 th; A current of electricity always takes the path of the least resistance. 


CHAPTER 10. THE PRINCIPLE OF THE DYNAMO AND MOTOR. 


Currents Induced by a Magnet.—Let four or five hundred turns of number 22 copper 
wire be wound into a coil C, as shown at Diagram 32 about 2% inches in diameter; let 
this coil be connected into circuits with a simple detector made by suspending in a box 
> with number 40 copper wire a coil of 200 

turns of number 30 copper wire; see Dia- 
A gram 32. Let the coil C be thrust sud¬ 

denly over the north pole of a strong 
horseshoe magnet, the deflection of the 
pointer P of the detector will indicate a 
momentary current flowing through the 
coil. Let the coil be held stationary over 
the magnet; the pointer will be found to 
come to a rest in its natural position. Now 
let the coil be removed suddenly from the 
pole; the pointer will move in a direction 
opposite to that of its first deflection, 
showing that a reverse current is now being generated in the coils. We learn, therefore, 
that a current of electricity may be induced in a conductor by causing the latter to move 
through a magnetic field, while a magnetic field has no such influence upon a conductor, 
which is at rest with respect to the field. This discovery, one of the most important in 
the history of science, was announced by the great Farraday in 1831. From it have 
sprung directly most of the modern industrial developments of electricity. 



1 lag *32 Induction of electric currents bv 
magnets 


CHAPTER 11. DIRECTION OF INDUCED CURRENTS. 


The Lenz Law.—In order to find the direction of the induced current let a small 
current from a primary cell be applied to the terminals A and B at Diagram 32, and 
note the direction in which the pointers move when the current enters, say at A. This 
will at once show in what direction the current was flowing in the coil C when it was 
being thrust over the norts pole. By a simple application to C of the right hand rule as 
illustrated in Diagram 21, we c.g,n tell which is the north and which is the south face 
of the coil, when the induced current is flowing through,it. In this way it will be found 
that if the coil was being moved past the north pole of the magnet, the current induced 
in it was in such a direction as to make the lower face of the coil a north pole during 
the downward motion, and a south pole during the upward motion. In the first case the 
repulsion of the north pole of the magnet and the north pole of the coil tend to oppose 
the motion of the coil while it is moving from A. to B, and the attraction of the north 
pole of the magnet and the south pole of the coil tends to oppose the motion while it 
is moving from B to C. In the second case the repulsion of the two north poles tends 
to oppose the motion between B and C, and the attraction between the north pole of 
the magnet and the south pole of the coil tends to oppose the upward motion from 










MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


21 


B to A. In every case, therefore, the motion is made against an opposing force. From 
these experiments, and others like them, we arrive at the following law: 


'WHENEVER A CURRENT IS INDUCED BY THE RELATIVE MOTION OF A 
MAGNETIC FIELD IN A CONDUCTOR, THE DIRECTION OF THE 
INDUCED CURRENT IS ALWAYS SUCH AS TO SET UP 
A MAGNETIC FIELD WHICH OPPOSES 
THE MOTION. 



This is the Lenz Law. This law might have been predicted at once from the 
principle of the conservation of energy, for this principle tells us that since an electric 
current possesses energy, such a current can appear only through the expenditure of 
mechanical work, or some other form of energy. 

Conditions Necessary for an Induced E M F.—Let the 
coil be held in the position shown in Diagram 33 and moved 
back and forth parallel to the magnetic field; that is paral¬ 
lel to the lines from north to south. No current will be 
induced by experiments of this sort. It is found that an 
E M F is induced in a coil only when the motion takes place 
in such a way as to change the total number of magnetic 
V jj lines of force, which are inclosed by the coil; or, to state 

^ this rule in a more general form, the LAW OF IN¬ 

DUCTION; WHENEVER A LOOP OF WIRE FORMING 
A CLOSED CIRCUIT IS PLACED IN A MAGNETIC 
FIELD, A CURRENT OF ELECTRICITY OR E M F 
WILL APPEAR IN THE WIRE WHENEVER THE 
STRENGTH OF THE MAGNETIC FIELD CHANGES; 
OR, WHEN THE WIRE OR CONDUCTOR IS PASSED 
THROUGH THE MAGNETIC FIELD SO THAT IT CUTS THE LINES OF FORCE AT 
RIGHT ANGLES. You must pay very close attention to the law of induction, and be 
very careful not to get the flow of magnetism confused with the flow of electricity, as 
the two are very easily mixed. Thus we find that all mechanical generators and motors 
depend upon the principle of the LAW OF INDUCTION. 


Mag. 33 Currents 
Induced only when 
conductor cuts lines 
of force 


CHAPTER 12. THE PRINCIPLE OF THE ELECTRIC MOTOR. 



Diag.34 The prin¬ 
ciple of the electric 
motor 


Let the vertical wire A B be rigidly attached to a hori¬ 
zontal wire G H, and let the latter be supported by a ring 
or other metallic support in the manner shown in Diagram 
34 so that A and B are free to oscillate about G and H as 
an axis; let the lower end of A B dip into a trough of 
mercury when a magnet is held in the position shown, and 
a current from a dry cell is sent down through the wire; 
the wire will instantly move in the direction indicated by 
the arrow F, viz, at right angles to the direction of the 
lines of magnetic force. Let the direction of the current 
in the wire be reversed, the direction of the force acting 
on the wire will be found to be reversed also. We learn, 
therefore, that a wire carrying a current in a magnetic 
field tends to move in a direction at right angles, both in 
the direction of the field and the direction of the current. 
This fact underlies the operation of all electric motors. 











22 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


The Motor and Dynamo Rule.—A convenient rule for determining A B, Diagram 
34 will move forward or backward in a given case, may be obtained as follows: If the 
fields of a magnet alone are represented by Diagram 35, and that due to the current 
alone by Diagram 36, then the resultant field, when the current bearing wire is placed 
between the poles of the magnet is that shown in Diagram 37. From the strength of the 
field above the wire is now the sum of the two separate fields, while the strength 




magnet alone 


current alone 


Dia&*37 Field of magnet 
and current 


below it is their difference. Faraday thought of the lines of force as acting like stretched 
rubber bands; this would mean that the wire in Diagram 37 would be pushed down. 
Whether the lines of force are so conceived or not, the motor rule may be stated thus: 

A current in a magnetic field tends to move away from the side on which its lines 
are added to those of the field. The dynamo rule follows at once from the motor rule 
and Lenz law, 

thus when a wire is moved through a magnetic field the current induced in it must be 
in such a direction as to oppose the motion; therefore, 

The induced current will be in such a direction as to increase the number of lines on 
the side towards which it is moving. 


CHAPTER 13. STRENGTH OF THE INDUCED CURRENT, OR E M F. 

The strength of an induced current is found to depend simply upon the number of 
lines of force cut per second by the conductor; or, in the case of of a coil, upon the rate 
of changes in the number of lines of force which pass through the coil. The strength 
of the current which flows is then given by the Ohms Law; that is, it is equal to the 
induced current divided by the resistance of the circuit. The number of lines of force 
which the conductor cuts per second may always be determined if we know the velocity 
of the conductor and the strength of the magnetic field through which it moves; for, it 
will be remembered that a field of unit strength is said to contain one line of force per 
square centimeter; a field of one thousand lines per centimeter in a conductor which is 
cutting lines at the rate of one hundred million per second, there is an induced current 
or E M F of one volt. The reason that we used a coil of 500 turns instead of a single 
turn in Diagram 32 was that by making a conductor in which the current was to be 
induced cut the lines of force of the magnet five hundred times instead of once, we 
obtain 500 times as strong an induced current and therefore 500 times as strong a 
current for a given resistance in the circuit. 



























MODERN ELECTRICAL MOTOR CAR EQUIPMENT 
CHAPTER 14. CIRCUITS INDUCED IN ROTATING COILS. 


Let a 400 or 500 turn coil of a number 28 copper 
wire be made small enough to rotate between the 
poles of a horseshoe magnet, and let it be connected 
into the circuit of the detector precisely as in Dia¬ 
gram 32, starting with the coil in the position as 
shown in Diagram 38. Let it be rotated suddenly 
clockwise, looking down from above through 180 
degrees; a strong deflection of the detector will be 
observed. Let it be rotated through the next 180 
degrees back to the starting point, and opposite de¬ 
flection will be observed. The arrangement is a 
dynamo in miniature. During the first half of revo¬ 
lution the wires on one of the right sides of the loop 
were cutting the lines of force in one direction, while 
the wires on the left side were cutting them in the opposite direction. A current was 
being generated down on the right side of the coil and up on the left side. 

The Dynamo Rule.—Thus, when a wire is moved through a magnetic field, the 
current induced in it must be in such a direction as to oppose the motion; therefore, the 
induced current will be in such a direction as to increase the number of lines on the 
side towards which it is moving. . It will be seen that both currents flow around the 
coil in the same direction. The induced current is the strongest when the coil is in* 
the position shown in Diagram 38-2, because there the lines of force are being cut most 
rapidly. Just as the coil is moving into or out of the position shown in Diagram 38-1 
it is moving parallel to the lines of force, and hence no current is induced, since no 
lines of force are being cut. As the coil moves through the last 180 degrees of its 
revolution, both sides are cutting the same lines of force as before, but they are cutting 
them in an opposite direction, hence the current generated during this last half is oppo¬ 
site in direction to that of the first half. 

CHAPTER 15. MECHANICAL GENERATORS OR DYNAMOS. 

Two distinct types of mechanical generators are in common use, and while their 
principles of action are practically the same, they differ somewhat in construction and 
application. The forms first used to succeed the battery were modifications of the large 
dynamo electrical machine used for delivering current for power and lighting. Later 
development resulted in the simplification of the dynamo, by which it was made lighter 
and more efficient, and the modem magneto igniter is the form which has received wide 
application. A dynamo uses electro-magnets to produce a magnetic field for the 
armature to revolve in, and is necessarily somewhat heavier and larger than a magneto 
of equal capacity because the field in the latter instrument is produced by permanent 
fields. An important advantage in using the magneto form of construction is that the 
weight of the windings is saved, because the permanent magnets retain their magnetism 
and do not require the continual energizing that an electro-magnet demands. The 
dynamo’s construction is superior where a continual drain is made upon the apparatus, 
because if a magneto is used continually the magnets will lose some of their strength, 
and as the magnetic field existing between the pole pieces decreases in value the amount 
of the current delivered by the apparatus diminishes in direct proportion. When electro¬ 
magnets are used, the constant flow of electric energy through the windings keeps 
them energized to the proper point, and as current is continually supplied, the strength 
of the magnetic field remains constant. The dynamo form of generator is used where 
currents of considerable value are needed, such as in electric lighting and starting 
systems so widely used now on the automobiles. Where the device is depended upon 
only to furnish ignition current, the magneto is preferred by most engineers because it 
is simpler and lighter than the dynamo, and also it may be made in such a form that 





Difig *38 Direction of cur¬ 
rents induced in a coil rotat¬ 
ing in a magnetic field 



















24 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


it will comprise a complete ignition system in itself. When a dynamo is utilized the 
conditions are just the same as far as necessary auxiliary apparatus is concerned, as 
though batteries were used, and one merely substitutes a mechanical generator in place 
of the chemical cells. The same auxiliary apparatus necessary in one case is employed 
in the other as well. A dynamo or magneto produces electricity by an inductive action, 
which is a reversal of the phenomenon by which a current of electricity will appear 
in a conductor which is placed in a magnetic field whenever the strength of the field is 
changed. 

CHAPTER 16. DYNAMOS. 


A Simple Alternating Current Dynamo.—The simplest form of commercial dynamo 
consists of a coil of wire so arranged as to rotate continuously between the poles of a 
powerful electro-magnet, as shown in Diagram 39. In order to make the magnetic field 

in which the conductor is moving as strong as 
possible, the coil is wound around an iron core 
C. This greatly increases the total number of 
lines of magnetic force which passes between 
N and S, for the core offers an iron path as 
shown in Diagram 40, instead of an air path. 
The rotating parts consist of the coil with its 
core which is called the armature. If the coil 
is wound in the manner shown in Diagram 39 
and 40, the armature is said to be of the ring 
type. If in the manner shown in Diagram 41, 
it is said to be of the drum type, as also in 
Diagram 42. The drum form of winding is 
used almost exclusively in modern machines; 
one end of the coil is attached to the insulated 
metallic ring R, which is attached rigidly to 
the shaft of the armature, and therefore rotates 
with it, while the other end of the coil is attached 
to a second ring R. The brushes B and B, which 
constitute the terminal of the external circuit, are 
always in contact with these rings. As the coil 
rotates an induced alternating current passes 
through the circuit. This current reverses direc¬ 
tion as often as the coil passes through the 
position shown in Diagram 40 and 42; that is the 
position in which the conductors are moving paral¬ 
lel to the lines of force, for at the instant the con¬ 
ductors which were moving up begin to move 
down, and those which were moving down begin 
to move up, the current reaches its maximum 
value when the coils are moving to a position 90 



Di£ r ’e«59 Ring-wound armature 



Diag«40 End view of ring 
armature 


degrees farther on, for then the lines of force are 
being cut most rapidly by the conductor on both 
sides of the coil. 

The Multipolar Alternator.—For most com¬ 
mercial purposes it is found desirable to have 120 
or more alterations of current per second. This 
could not be attained easily with two pole ma¬ 
chines like those sketched from Diagram 39 to 
42, hence, commercial alternators are usually built 
with a larger number of poles alternately, then N 
and S arranged around the circumference of a 



Diag.41 JlTuin-wound armature 
















































MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


25 



Diag.42 End view of drum 
armature 


circle in the manner shown in Diagram 43. The 
dotted lines represent the direction of the lines of 
force through the iron. It will be seen that the 
coils which are passing beneath north pole have 
induced current set up in them. The direction of 
which is opposite to the currents which are in- 
induced current set up in them, the direction of 
the south pole. Since, however, the direction of 
windings of the armature coil change between 
each two poles, all the inductive efforts of all the 
poles are added to the coils, and constitute at any 
instant one single current flowing around the 
complete circuit in the manner indicated by the 


arrows in the Diagram 43. The current reverses 
direction at the instant at which all the coils pass 
the midway point between north and south poles. 

The number of alternations per second is equal to 
the number of poles multiplied by the number of 
revolutions per second. The field magnets N and 
S of such a dynamo are usually excited by a direct 
current from some other source. 

The Principle of the Commutator.—By the 
use of a so-called commutator it is possible to 
transform a current which is alternating in the 
coil of the armature to one which always flows in 
the same direction through the external portion 
of the circuit. The simplest possible form of such 
a commutator is shown in Diagram 44. It con¬ 
sists of a single metallic ring which is split into 
two equal insulated semicircular segments, A and 

C. One end of the rotating coil is soldered to one 
of these semicircles, and the other end to the 
other semicircle. Brushes B and B are set in such 
positions that they lose contact with one semi¬ 
circle and make contact with the other at the in¬ 
stant at which the current changes direction in 
the armature; the current, therefore, always 
passes out to the external circuit through the 
same brush, while a current from such a coil and 
commutator as that shown in Diagram 44 would 
direction through 



Dlag *43 Diagram of alternating- 
current dynamo 



Disg.44 The simple commutator 


always go in the same 
the external circuit. It would be of a pulsating 
rather than a steady character, for it would rise 
to a maximum and fall again to zero twice during 
each revolution of the armature. This effect is 
avoided in the commercial direct-current dynamo 
by building a commutator of a large number of 
segments instead of two, and connecting each to 
a portion of the armature coil in the manner 
shown in Diagram 45. 

The Ring Armature Direct Current Dynamo. 

_Diagram 45 illustrates the construction of a 

commercial two-pole direct current dynamo of the 
ring armature type. The figure represents an end 



Disg • 45 Two-pole direct-current 
dynamo with ring armature 













































MODERN ELECTRICAL MOTOR CAR EQUIPMENT 



dynamo, ring-armature type 


view of a core like that shown in Diagram 3$. 
The coil is wound continuously around the core, 
each segment being connected to a corresponding 
segment of the commutator in the manner shown 
in Diagram 45. At a given instant currents are 
being induced in the same direction in all the 
conductors outside of the core on the left half side 
of the armature. The cross on these conductors 
representing the tail of a retreating arrow is to 
indicate that these currents flow away from the 
reader. No E M F is induced in the conductor on 
the inner side of the ring since these conductors 
cut no lines of force. See Diagram 40. Nor is 



there any current induced in the conductors at the 
top and bottom of the rings where the motion is 
parallel to the magnetic lines. The addition of 
these similarly direct currents in the various con¬ 
volutions of the continuous coil on the left side 
of the ring constitutes one single current flowing 
upward towards the brush B, (see arrows). On 
the right half of the ring on the other hand the 
induced currents are all in the opposite direction; 
that is, towards the reader, since the conductors 
are here all moving up instead of down. The dots 

in the middle of these conductors represent the direc* - 

heads of an approaching arrow. The summation w Current 

of these currents constitutes one single current, Dynamo .Drum 

also flowing upward in the right half of the coils binding 

towards the brush B. These two currents form the two halves of the ring, pass out at B 
through the external circuit, and back at B. This condition always exists, no matter 
how fast the rotation, for it will be seen that as each loop rotates into the position 
where the direction of this current reverses, it passes a brush and therefore, at once 
becomes a part of the circuit on the other half of the ring where the currents are all 
flowing in the opposite direction. If the machine is of the four-pole type like that 
shown in Diagram 46, the current flows towards two mutual points or points of no 
induction instead of towards one as in two-pole machine, and they flow away from 
two other neutral points, see p p p p, Diagram 46, hence there are four brushes, two 
positive and two negative. Since the two positive and two negative brushes are con¬ 
nected as shown, both sets of current flow off to the external circuit on a single wire. 
The figure with its arrows will explain completely the generation of current by a four- 
pole machine. 


The Drum Armature Direct Current Dynamo.—The drum wound armature shown in 
section in Diagram 47 has an advantage over the ring armature in that while the con¬ 
ductors on the inside of the latter never cut lines of force and are therefore always 
idle, in the former all of the conductors are cutting lines of force except when they are 
passing the neutral points; in theory, however, the operation of the drum armature is 
precisely the same as that of the ring armature. All of the conductors on the left 
side of the line connecting the brushes, see Diagram 47, carry induced currents which 
flow in one direction, while all the conductors on the right side of this line have opposite 
currents induced in them. It will be seen, however, in tracing out the connections 1 1 
2 2, 3 3, etc., of Diagram 47, the dotted lines represent connections at the back of the 
drum that the coil is so wound about the drum that the current in both halves are 
always flowing towards one brush B, from which they are led to the external circuit. 










MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


27 


Series, Shunt, and Compound Wound Dynamos.—In direct current machines the 
field magnets N S is excited by the current which the dynamo itself produces. In the 
so-called shunt wound machines, a small portion of the current is led off from the 
brushes through a great many turns of fine wire which encircle the core of the magnet, 
while the rest of the current flows through the external circuit. See Diagram 48. In the 
so-called Series Wound Dynamo, Diagram 49, the whole of the current is carried through 
a few turns of coarse wire which encircle the field magnet. These turns are then in 
series with the external circuit. In the compound wound machines, Diagram 50, there 
is both a series and a shunt coil. By this arrangement, it is possible to maintain a 


Main Circuit 



Main Circuit 



Diag.48 gjjunt-IDiflg.49 The series-Jj)iag«50 The compound- 

wound dynamo wound dynamo wound dynamo 


constant potential difference between the brushes, no matter how much the resistance 
of the external circuit may be varied, hence, for purposes in which a varying current is 
demanded, as incandescent lighting and operating of street cars, compound wound 
dynamos are most exclusively used. In all these types of self-exciting machines there 
is enough residual magnetism left in the iron core after stopping to start feeble induced 
currents when started up again. These currents immediately increase the strength of 
the magnetic field, and so the machine quickly builds up its current until the limits of 
magnetizing are reached. 



Diag.Sl-The Permanent mag¬ 
nets. (la) — The pole pieces. 
(11a)—The base (12a)—usually 
of brass or aluminum. 


PERMANENT 

^MAGNETS 



COPPER WIRE 
ON ARMATURE 


Di&g .5% View cfa Low Tension 


Magneto with the end plate off 
and armature shown in section. 




































































28 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


The Construction of a Low 
magnets 1-a. The pole pieces 



Blag.53-The Low Ten¬ 
sion Magneto complete. 
View shows the drive 
and of the armature, 
which is driven at a fixed 
•peed from crank shaft 
of engine, by gear or 
chains. 

The armature has one 
winding. 


Tension Magneto.—Diagram 51 illustrates the permanent 
11-a, the base 12-a—usually made of brass or aluminum. 
Diagram 52 is a view of a low tension magneto with 
the end plates off and the armature shown in section; 
one, permanent magnets magnetized at all times; 
two, the armature revolves with a gear connected 
with the engine shaft. Note that a single winding *f 
insulated copper wire is wound on the armature. Dia¬ 
gram 53 illustrates the low tension magneto, complete 
view, showing the driving end of the armature whi*h 
is driven at fixed speed from the crank shaft of the 
engine, by gears or chain. The armature has one 
winding. In Diagram 54 the magneto is also a me¬ 
chanical generator, but the current generated is 
alternating; that is, the current is not a steady flow, 
but alternates continuously. The field magnets are 
always of the permanent magnet type. The arma¬ 
ture for generating alternating currents is of two 
types; the shuttle type, as shown in Figures 3 and 4, 
and the inductor type which we will take up and ex¬ 
plain next. The shuttle type of armature has a pri¬ 
mary wire winding of copper wire, one end grounded 
to the armature core, and the other end insulated as 
illustrated in Figure 4, Diagram 54. 

If there is but one winding on the armature it is 
called a primary winding, and is of low voltage, 
about six volts; therefore it is called a low tension 
magneto. 



sect ion 


Parts of the Low Tension Magneto Shuttle Type Armature.—Diagram 55 illustrates 
the necessary parts constituting the shuttle armature, or H type. Bronze heads B B 
screw to the armature core C and C, shafts A A are driven and riveted to bronze 
heads; wire is wrapped around the space C and C. It will be seen that the core is not 
a solid casting; rather, it is a pair of castings between which is clamped a group of soft 
iron stampings, D, having the form shown in the detailed sketch 55. The object of 
thus laminating the core, as it is called, is to retard the circulation of eddy currents im 
the core due to induction. The same forces of induction which are at play in the 





























































_MODERN ELECTRICAL MOTOR CAR EQUIPMENT 2§ 

windings operate also in the iron core itself, and if unchecked, would both consume 
power and heat the armature unduly. As the voltage of the currents is very low. 



3iag«55 j|>art3 of the Low Tension Magneto Shuttle 
type armature/ 




even the slight obstruction of the lamination is sufficient to retard them. The laminated 
section of the armature is shown at D. Laminated means that instead of the casting 
<3 being solid there are several layers of flat iron placed together C, as shown at D. 

How Currents Are Made to Alternate in the Windings of 
Armatures.—Referring to Diagram 56, figure 1, the lines of force 
are passing through the armature upward from N to S and con¬ 
tinue until they reach the position shown in Figure 3. The lines 
will then pass through the armature downward from N to S, 
thus reversing the flow. This reversal occurs twice during every 
revolution of the armature. When armature is in the position 
shown in figure 3 the current strength is at its maximum, and 
is the position in which it should be placed when the current is 
broken or interrupted for transforming purposes. As the arma¬ 
ture revolves between the pole pieces in.the magnetic field, the 
polarity changes twice in every revolution, which causes the loop 
of wire or conductor to be in a magnetic field, and the strength 
of that field is changed twice in a revolution, which causes an 
impulse or an electric current to appear in the wire, and it is 
this gurrent which is utilized for creating the magnetic field in 
the transformer which is further utilized for ignition purposes 
in the automobile. 

The Inductor Type Armature Magneto is shown in Diagram 
57. This electrical generator is built in such a manner that it 
forms a part of the power plant. The magnetic field is produced 
by a series of revolving magnets which are joined to and turn 
with the fly wheel of the engine.. The armature coils are carried 
by a fixed plate which is attached to the engine base. This 
apparatus is really a magneto having a revolving field and a 
fixed armature, and as the magnets are driven from the fly 
wheel there is no driving connection to get out of order and 
cause trouble. As the coils in which the current is generated 
are stationary, no commutator or brushes are needed to collect the current, because the 
electricity may be easily taken from the fixed coils by direct connection. This type is 
known as the Ford Magneto. This magneto generates a low voltage of about 6 to 30 
volts or slightly more, owing to the speed. The current generated is alternating. This 
is also called an inductor type armature because the coils of wire, called the stationary 
armature, remain stationary, and the inductor or magnets, called the rotating field, re- 



Diag. # 56 
Kow th© cur¬ 
rent is made 
to alternate 
in the wind¬ 
ings of Ar¬ 
mature 


















30 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


volve. Instead of there being two impulses per revolution there are sixteen impulses 
per revolution, because there are sixteen coils and sixteen inductors or magnets. In other 
words, each revolution of the fly wheel to which the magnets are attached means one 
revolution of the crank shaft. There are sixteen positions of the magneto when the 
current'output is at its maximum height, and each of these positions is called the peak * 



Biag.57 Distinctive Form of Current Producer Used on Ford Cars is Incor 
porated in the Power Plant Fiy Wheel. 

of the current wave; there are also sixteen positions, during which the current is not 
flowing at all; each of these is called the neutral position, and each is half way between 
two peaks; therefore, every sixteenth of a revolution of the magneto a position is 
reached where no current is being generated. Each alternating peak or impulse is of an 
opposite polarity; that is, there are eight positions in each revolution when the current 
which flows from the magnet windings to the lights is positive, and between these 
positives are eight other positions when the current is negative; Therefore, the Ford 
magneto, the shuttle type, low tension magneto, the dynamo, the storage battery, or dry 
cell, are utilized on the automobile as a means of producing a primary current which 
would be valueless unless suitable apparatus for stepping up this current, or in other 
words, transforming it from a low tension current to one of high voltage, and also 
suitable apparatus for timing and regulating this high tension current so that it can 
be controlled and be made to appear in the combustion chamber at the proper time. 



























MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


SI 


CHAPTER 17. THE PRINCIPLE OF THE INDUCTION COIL AND TRANSFORMER. 

CURRENTS INDUCED BY VARYING THE STRENGTH OF A MAGNETIC 
FIELD. Let about 500 turns of number 28 copper wire be wound around one end of 
an iron core as shown in Diagram 58, and connected to the circuit of a galvometer or 
current detector; let about 500 more turns be wrapped about another portion of the core 
and connect into the circuit of two dry cells, when the key K is closed, the deflection of 
the galvometer or indicator will indicate that a temporary current has been induced in 
one direction through the coil S, and when it is opened an equal but opposite deflection 
will indicate an equal current flowing in the opposite direction. The experiment illus¬ 
trates the principle of the induction coil and the transformer. The coil P in Diagram 58 
which is connected to the source of the current is called the primary coil, and the coil 
S in which the currents are induced is called the secondary coil, causing the lines of 
force to spring into existence inside of S; or in other words, magnetizing the space in¬ 
side of S has caused an induced current to flow in S, and demagnetizing the space inside 
of S has also induced a current in S with the general principle stated, thus that any 
change in the number of magnetic lines of force which threads through a coil induces a 
current in the coil, or WHENEVER A LOOP OF WIRE FORMING A CLOSED CIR¬ 
CUIT IS PLACED IN THE MAGNETIC FIELD A CURRENT OF ELECTRICITY 
WILL APPEAR IN THE WIRE WHENEVER THE STRENGTH OF THE FIELD IS 
CHANGED. We may think of the lines as always existent as closed loops which col¬ 
lapse under demagnetization to mere double lines at the axis of the coil. Upon mag¬ 
netization one of these two lines spring out, cutting the encircling conductor and induc¬ 
ing the current. WW 



Diagram 58. Induction of current by mag¬ 
netizing and demagnetizing an iron core. 

The Direction of the Induced Currents.—The Lenz Law which will be remembered, 
following from the principle of the conservation of energy, enables us to predict at once 
the direction of the induced current in the above experiment, and an observation of the 
deflection of the galvometer enables us to verify the correctness of the prediction. Con¬ 
sidering first the case in which the primary circuit is made, and the core thus magne¬ 
tized; according to the Lenz Law the current induced in the secondary circuit must be 
in such a direction as to oppose the change which is being induced by the primary cur¬ 
rent; that is, in such a direction as to tend to magnetize the core oppositely to the 
direction in which it is being magnetized by the primary. This means, of course, that 
the induced currents in the secondary must encircle the core in a direction opposite to 
the direction in which the primary current encircled it. We learned, therefore, that on 
making the current in the primary the current induced in the secondary is opposite to 
that in the primary. When the current in the primary is broken, the magnetic field 
created by the primary tends to die out; hence, by the Lenz Law the current induced in 
the secondary must be in such a direction as to tend to oppose the process of demagne¬ 
tization; that is, in such a direction as to magnetize the core in the same direction in 
which it is magnetized by the decaying current in the primary; therefore, the current 
induced in the secondary at breaking the current induced in the secondary is in the same 
direction as that in the primary. 

E M F in the Secondary.—If half of the 50t) turns of the secondary as shown in 
Diagram 58 are unwrapped the deflection will be found to be just half as great as be¬ 
fore- since the resistance of the circuit has not been changed we learn from this-that 













32 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


the E M F of the secondary is proportional to the number of turns of wires in it. If 
we wish to develop a very high current in the secondary we have only to make it of a 
very large number of turns of fine wire. 

Self Induction.—If in the experiment illustrated in Diagram 58 the coil S had been 
made a part of the same circuit as P, the E M F induced in it by the change in the 
magnetism of the core would of course have been just the same. In other words, when 
a current starts in a coil the magnetic field which it itself produces tends to induce a 
-current opposite in direction to that of the starting current; that is, tends to oppose the 
starting of the current; and when a current in a coil stops, the collapse of its own mag¬ 
netic field tends to induce a current in the same direction as that of the stopping cur¬ 
rent; that is, tends to oppose the stopping of the current. This means merely that a 
current in a coil acts as though it had inertia and opposes any attempt to start or 
stop it. This inertia-like effect of a coil itself is called self-induction. Let a few dry 
cells be inserted into a circuit containing a coil of a large number of turns of wire, the 
circuit being closed at some point by touching two bare copper wires together, holding 
■the bare wires in the fingers; break the circuit between the hands and observe the 
shock due to the current which the E M F or self induction sent through your body. 
Without the coil in the circuit you will obtain no such shock, though the current stops 
when you break the circuit will be many times larger. The spark coil of the automo¬ 
bile is a good illustration of a device for producing a spark due to self induction. 

The Induction Coil.- —The induction coil as usually made, Diagram 59, consists of a 
soft iron core, C, composed of a bundle of soft iron wires, a .primary coil, P, wrapped 
around this core and consisting of say 200 turns of copper wire; for example, Number 16, 
which is connected into the circuit of a battery through the contact poini?s at the end 
of the screw, D. A secondary coil, S, surrounding the primary in the manner indi¬ 
cated in the diagram and consists generally of between 30,000 and 100,000 turns of 
number 35 copper wire, the terminals of which are the points T T, and a hammer B or 



other automatic arrangement for making and breaking the circuit of the primary. Let 
the hammer B be held away from the opposite contact points by means of the fingers, 
then touch to this point, then pull quickly away, a spark will be found to pass between 
T and T at break only, never at make. This is on account of the opposing influence at 
make of self-induction in the primary. The magnetic field about the primary rises very 
gi-adually to its full strength, and hence its lines pass into the secondary coil compara¬ 
tively slowly; at break, however, by separating the contact points quickly we can make 
the circuit at the primary fall to zero in an exceedingly short time, perhaps not mere 
than one hundred thousandth part of a second; that is, we can make all of its lines pass 
out of a coil in this time, hence the rate at which the lines thread through or cut the 
secondary is perhaps ten thousand times as great at break as at make, and therefore 
the E M F is also something like ten thousand times as great. In the normal use of the 
coil the primary is automatically made and broken at B by means of a magnet and the 
spring, precisely as in the case of the electric bell. Let the student analyze this part of 
the coil for himself. The condenser shown in diagram 59, with its two sets of plates 
























MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


33 


connected to the conductor on either side of a spark gap between R and D, is not an 
essential part of a coil, but when it is introduced it is found that the lengtn of the spark 
which can be sent across between T and T is considerably increased. The reason is as 
follows: when the circuit is broken at B the inertia, that is, the self induction of the 
primary current, tends to make a spark jump across from D to B, and if this happens 
the current continues to flow through this spark or arc until the terminals have become 
separated through a considerable distance. This makes the current die down gradually 
instead of suddenly, and does not produce a high E M F; but when a condenser is 
inserted, as soon as B begins to leave D the current begins to flow into the condenser, 
and this gives the hammer time to get so far away from D that an arc cannot be 
formed. This means a sudden break and a high E M F. Since a spark passes between 
T and T only at break it must always pass in the same direction. Coils which give 24 
inch spark perhaps 500,000 volts, are not uncommon; such coils usually have hundreds 
of miles of wire upon their secondaries. 

Laminated Cores Foucault Currents.—The core of an induction coil should always be 
made of a bundle of soft iron wires insulated from one another by means of shellac or 

varnish, see Diagram 60, for whenever a current is started 
or stopped in the primary, P, of a coil furnished with a 
solid iron core, see Diagram 61, the change in the magneie 
field of ihe primary induces a current in the conducting 
core, C, for the same reason that it induced one in the 
secondary S. This current flows around the body of the 
core in the same direction as the induced current in the 
secondary S; that is, in the direction of the arrows. The 
only effects of these so-called eddies, or foucault currents, 
is to heat the core, and this is obviously a waste of energy. 
If we can prevent the appearance of these currents, all of 
the energy which they would waste in heating the core 
may be made to appear in the current of the secondary. 

The core is therefore built of varnished iron wire, which 
runs parallel to the axis of the coil; that is, perpendicular 
to the direction in which the current would be induced. The 
induced E M F therefore finds no closed circuit in which to 
set up a current. It is for the same reason that the 
iron cores of dynamos and motor armatures, in¬ 
stead of being solid consist of iron discs placed side by 
side, as shown in Diagram 62, and insulated from one 

another by a film of oxide. A core of this kind is called a laminated core. It will be 
seen that in all such cores the space or slots between the laminations must run at right 



Piag. bZ Laminated drum-armature 
core with commutator, showing one 
coil wound on the core 


angles to the direction of the induced E M F; that is, perpendicular to the conductor 
upon the core. 



Diag.61 Diagram 
showing eddy cur 
rents in solid core 



Piag. 60 Core of in 7 
sulated iron wires. 















34 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


The Transformer.—The commercial transformer is a modified form of induction coil. 
The chief difference is that the core, R, Diagram 63, instead of being straight is bent 

into the form of a ring, or is given other shapes, such that 
the magnetic lines of force have a continuous iron path. 
Instead of being obliged to push out into the air as in the 
induction coil; furthermore, it is always an alternating 
current instead of an intermittent current which is sent 
through the primary A. Sending such a current through 
A, is equivalent to magnetizing the core first in one di¬ 
rection, then demagnetizing it, then magnetizing it in the 
opposite direction. The result of these changes in the 
magnetizing of the core causes the secondary B to be in a 
magnetic field which is constantly being changed, and as 
the law of induction states, THAT A LOOP OF WIRE 
FORMING A CLOSED CIRCUIT BEING PLACED IN A MAGNETIC FIELD, A 
CURRENT OF ELECTRICITY WILL APPEAR IN THE WIRE WHENEVER THE 
STRENGTH OF THE FIELD IS CHANGED, is thus utilized to good advantage. 

The Use of the Transformer.—The use of the transformer is to convert an alternat¬ 
ing current from one voltage to another, which, for some reason, is found to be more 
convenient. For example, in electric lighting where an alternating current is used, the 
E M F generated by the dynamo is usually either 1100 volts or 2200 volts, a voltage too 



Di a S*'^Diagram of 
transformer 


Main Conauotor 



DiSg -^Alternating current lighting circuit 
with transformers 


high to be introduced safely into private homes, hence transformers are connected across 
the main conductor in the manner shown in diagram 64. The current which passes into 
the house to supply the lamps does not come directly from the dynamo; it is an induced 
current generated in the transformer. 

Pressure in Primary and Secondary.—If there are a few turns in the primary and 
a large number in the secondary, the transformer is called a step-up transformer, be¬ 
cause the voltage produced at the terminals of the secondary is greater than applied 
at the terminals of the primary; thus an induction coil is a step-up transformer. In 
electric lighting, however, transformers are mostly of the step-down type; that is a 
high pressure, say 22d0 volts, is applied at the terminals of the primary, and a low 
pressure, say 110 volts, is obtained at the terminals of the secondary. In such a trans¬ 
former the primary will have twenty times as many turns as the secondary. In general 
the ratio between the voltage at the terminals of the primary and secondary is the 
ratio of the number of turns of wire upon the two. 

Efficiency of the Transformer.—In a perfect transformer the efficiency would be 
unity. This means that the electrical energy put into the primary, that is, the volts 























MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


35 


applied to its terminals, times the amperes flowing through it, would be exactly equal 
to the energy taken out in the secondary; that is, the volts generated in it times the 
strength of the induced current; and in fact, in actual transformers the latter produce 
is often more than 97% of the former; that is, there is less than 3% loss of enei-gy in 
the transformation. This loss of energy appears as heat in the transformer. This 
transfer which goes on in a big transformer of huge quantities of power from one circuit 
to another entirely independent circuit, without noise or motion of any sort and almost 
without loss is one of the most wonderful phenomenon of modern industrial life. 

' ! } 

CHAPTER 18. ELECTRICAL TRANSMISSION OF POWER. 

Since the electrical energy produced by a dynamo is equal to the produce of the 
E M F generated by the current furnished, it is evident that in order to transmit from 
one point to another a given number of watts, say ten thousand, it is possible to have 
either an E M F of one hundred volts and a current of one hundred amperes, or an E M F 
of one thousand volts and a current of ten amperes. In the two cases, however, the 
loss of energy in the wires which carry the current from the place where it is generated 
to the place where it is used, will be widely different. If R represents the resistance of 
this transmitting wire, the so-called line, and C the current flowing through it, the 
energy wasted in heating the line will be but one hundredth times as much in the case 
of the high voltage, ten ampere current, as in the case of low voltage and one hundred 
ampere current; hence for long distance transmissions, where line losses are considerable, 
it is important to use the highest possible voltage, but on account of the difficulty of 
insulating the commutator segments from one another, voltage higher than seven or 
eight hundred cannot be obtained with direct current dynamos. 

With alternator generators, however, the difficulty of insulation is very much less, 
on account of the absence of a commutator. The large, ten thousand horse power 
alternating current dynamos on the Canadian side of Niagara Falls generate directly 
twelve thousand volts. This is the highest voltage thus far produced by generators. 
In all cases where these high pressurs are employed they are transformed down at the 
receiving end of the line to a safe and convenient voltage from 50 to 500 volts by means 
of step-down transformers. It will be seen from the above facts that only alternating 
currents are suitable for long distance transmission. Plants are now in operation 
which transmit power as far as one hundred and fifty miles and use pressure as high 
as 100,000 volts. In all such cases step-up transformers suited at the power house 
transfer the electrical energy developed by the generator to the line and step-down trans¬ 
formers suited at the receiving end, transfer it to th motor or lamps which are to be 
supplied. 

The generators used on the American side of Niagara Falls produce a pressure of 
2300 volts, for transmission to Buffalo, twenty miles away. This is transformed up to 
22000 volts. At Buffalo it is transformed down to the voltage suitable for operating 
the street car lines and factories of the city. On the Canadian side the generators pro¬ 
duce current at 12000 volts as stated, and these are transformed up for long distance 
transmission to 22,000, 40,000 and 60,000 volts. 



36 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


CHAPTER 19. IGNITION SYSTEMS OUTLINED. 

One of the most important auxiliary groups of the gasoline engine comprising the 
automobile power plant, and one absolutely necessary to insure engine action, is the 
ignition system which is the spark of life to the engine, or the method employed of 
kindling the compressed gas in the cylinder to produce an explosion and useful power. 
The ignition system has been fully as well developed as other parts of the automobile, 
and at the present time practically all ignition systems follow principles which have 
become standard through wide acceptance; therefore, at the present time, all gas engines 
in automobile construction utilize an electrical ignition system in which the compressed 
gas is exploded by the heating value of the minute electric arc or spark in the cylinders. 
Two general forms of electrical ignition systems may be used, the most popular being 
that in which a current of electricity under high voltage is made to leap a gap or air 
space between the points of the spark plug screwed into the cylinder. 

The other form, which has been almost entirely abandoned in automobile practice, 
but which is used to some extent on marine engines and stationary types, is called the 
low tension system, because a current of low voltage is used and the spark is produced 
by moving the electrodes in the combustion chamber. The essential elements of any 
electrical ignition system, either high or low tension, are first a simple and practical 
method of current production; second, suitable timing apparatus to cause the spark to 
occur at the right point in the cycle of engine action; third, it must have a coil or trans¬ 
former to step up the current so the voltage will be high enough to overcome the 
resistance in the spark gap in the cylinders and thus produce the arc or spark; fourth, 
suitable wiring and distributing apparatus and an arrangement in the combustion 
chamber to produce the spark. 

Timer and Distributor Forms.—Anyone familiar with the basic principle of internal 
combustion engine action will recognize the need of incorporating some device in the 
ignition system which will insure that the igniting spark will occur only in the cylinder 
that is ready to be fired at the right time in the cycle of operation. There is a certain 
definite point at which the spark must take place, this having been determined to be at 
the end of compression upstroke, at which time the gas has been properly compacted 
and the piston is about to start returning to the bottom of the cylinder. The Timer is 
a mechanical switch driven by the engine and is used to connect up or break or interrupt 
the primary circuit at the time the spark is needed in the cylinders. A distributor is a 
mechanical switch driven by the engine and is used to distribute the high tension current 
to the cylinders according to the filling order. These mechanical forms of switches are 
designed so that hundreds of positive contacts which are necessary to close and open a 
circuit may be made per minute without failure. When the device is employed to open 
and close a low tension circuit it is known as a commutator or timer, and when it is 
ust d in connection with currents of high voltage they are called secondary distributors. 
Certain constructional details make one form differ from the other, and while they per¬ 
form the same function they vary in design. Such timing and distributing devices are 
always driven by positive gearing from the engine, and are timed so the spark will 
oc'ur in the cylinders at just the proper time. 

m- 

The Vibrator; Its Purpose.—As a secondary current in the coil only flows when the 
primary current begins to flow and is suddenly interrupted, this necessitates an arrange¬ 
ment to complete the primary circuit so that the battery current flowing through the 
primary winding, and then breaking the circuits so that the battery current stops flow¬ 
ing, or is interrupted from flowing. This causes the SECONDARY WINDING TO BE 
IN A MAGNETIC FIELD, AND THEN THE STRENGTH OF THE FIELD IS SUD¬ 
DENLY CHANGED, WHICH PRODUCES A CURRENT IN THE SECONDARY 




t 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 37 

WINDING which is utilized to jump the gap in the spark plug at the right time if 
properly controlled. This arrangement is called a vibrator, and it may operate in two 
different ways, electrical or magnetical, and mechanically. 

A Magnetic Vibrator.—The magnetic vibrator depends on the magnetism produced 
in the core of the coil when the primary current passes, as shown in Diagram 65. A flat 
spring called the vibrator spring or blade is so placed that one end of it is opposite to 
the end of the core, the other end being firmly supported. Touching the vibrator spring 
near its free end is the points of contact with the adjusting screw. When a low voltage 
current flows through the primary winding the core becomes a magnet and attracts the 
free end of the vibrator spring, drawing it away from the adjusting screw. As soon 



Dlage65 Amgaetlc Type of Vibrator 


as the attraction draws the vibrator spring out of contact with the adjusting screw the 
circuit is broken, the current stops flowing in the primary coil, and the core ceases to 
be a magnet, and the vibrator spring being no longer attracted by the magnetism it 
springs back again, making contact with the adjusting screw. This again closes the 
circuit, and the vibrator spring is again attracted by the magnetism, thus the circuit, 
through the vibrating springs and adjusting screw is broken and made again as long as 
the commutator or timer keeps the primary circuit closed through its contact. 

Mechanical Vibrator.—A mechanical vibrator is shown in diagram 66. When this type 
of vibrator is used, the vibrators on the coil are not required, as the vibration of the flat 
spring against the adjusting screw causes the contact to be suddenly opened and closed 
by the cam during which time the flat spring vibrates mechanically, causing the primary 
circuit to be broken, which changes the strength of the magnetic field in the core, thus 
producing the induced current to flow in the secondary winding of the coil. The 
mechanical vibrator consists of a flat spring with a smail weight on one end, and the 
other end is attached to a post. The weight rests on the iron rim of a small cam with 
a notch in it so that when it turns the weight drops into the notch. One wire from the 
primary circuit is attached to the flat spring, and the other wire of the primary to an 
adjusting screw. When the weight, called the bob, is in the notch of the cam, the flat 
spring makes contact with the adjusting screw and the current flows around the pri¬ 
mary winding of the core, thus producing the magnetic field, but the cam, in continuing 
to turn moves the weight out of the notch which separates the flat spring from the 
screw and breaks the circuit. Because of the springiness of the flat spring, it vibrates 



























38 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


when the weight drops into the notch, making and breaking the current. By making 
and breaking the contact in this way, the primary flows through the primary winding 


FROM 

B#-TT£gY 



K/.AT 


WEIGHT 


ATTACHED TO. SPARK LEVER 
TO cent 


adjusting 

SCAEW 


GAM 


Mechanical Vibrator 


always flowing and stopping each time the vibrator makes and breaks the circuit. This 
produces a corresponding current in the secondary winding, which is sent to the 
distributor and there distributed to the cylinders according to the firing order. 

Low Tension Coil System of Ignition.—We have learned the different sources from 
which electricity can be obtained for ignition. The principle of ignition which is the 



old style make and break ignitor uses a low tension or primary coil. This system ia 
seldom used only on stationary engines; however, it will be well for the reader to master 











































MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


39 


the principles of the low tension coil, as it is the foundation for the building up of a high 
tension coil or magneto armature winding. The current is strengthened or intensified 
by the use of a simple coil called a primary or low tension coil. At diagram 67 we have 
a diagram of a make and break low tension system of ignition. The ignitor is shown 
which makes and breaks the low tension current as it flows from the positive pole of the 
battery to the single wound low tension coil through the switch and then through the 
insulated electrodes in the combustion chamber and then returns through the metal of the 
engine to the negative ground and there back to where it started from. When the nose 
of the cam strikes the tappet rod this rod makes and breaks the flow of current and 
creates a flash or spark which is utilized to set the mixture on fire in the combustion 
chamber. 

Purpose of Spark Plugs.—You are more or less familiar with the ordinary spark 
plug that is used in connection with the ignition system to produce a spark inside the 
cylinders of the engine. In Diagram 68 are two views of two typical spark plugs, one 
showing plug as if it were cut in two, called a sectional view, the other view showing 
plug dissembled. The metal part of the plug T acts as a conductor of a current while 
the porcelain C represents the insulating material which is composed of porcelain or 



Tig. 2—Names of Parts of Insulated 

Spark Plug, EspociaUy Made for Magneto Use. 
Note the heavy terminals. Magnetos give a 
heavy “fat” spark, but points are set very closes. 
(1/64-inch.) 



Fig. 3—Parts of a Porcelain insulated (C), 
Spark Plug Separated. A Type of Plug Usually 
used with a Jump Spark Coil System of Ignition, 

S—Is the iron shell which screws into the 
engine cylinder. 

N—Is the brass bushing which holds the 
porcelain (0) in the iron shell. 

C—-Is the porcelain with rod (T) running 
through it. . ...... 

B—Is the lock, nut or thumb nut which holds 
the secondary wire. (B) screws on the end 
of (T) to hold wire in place. 


h.) ' > -- - - 

Diag. # G8 Parts and sectional view of a Spark Plug 


mica, an insulator of electricity. A spark plug is screwed into each cylinder of the 
engine, and when the piston is in the right position to receive a spark, a current of 
electricity is sent along the metal center part, called the firing pin of the spark plug, 
and across the small air gap at the bottom, and into the outer sleeve. Although this air 
gap is only about one sixty-fourth to one thirty-second of an inch wide, the air in the gap 
offers such a tremendous resistance to the current that it requires in the neighborhood 
of ten to twenty thousand volts of pressure to force a very small quantity of 







































40 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


current across the gap; in other words, the current must be of such high pressure that 
it will jump across a space between two points, forming a spark as it passes. The current 
produced by a battery and low tension coil as used on the make and break system would 
not have enough pressure to jump across this gap; therefore, it must be intensified, or 


COIL 


metal 

f?OD_ 


SECONDARY MRE TO STARK PL OO 

_ <S-— 


INTAKE, 
VALVE R 



CRQURD 
PATH 0? 

CURRENT THRU 
ENGINE, TO 
METAL POLLER 



Patteky] 

X 

• 


lDiag .69 -An exaggerated drawing, made for the purpose ©f illustrating how the spark plug m 
screwed into the conibustioD chamber of the engine, and how the current is carried from the 
through the primary winding of the coil, to - mmutator etc Trace the circuit, with your pen.' 


the pressure increased still more. This is accomplished by adding a coil of another kind, 
called the secondary coil, around the primary coil, ard is used to intensify the current 
sufficiently to force it to jump across the open space; therefore it is called the jump 
Spark or high tension, meaning high pressure. 


CHAPTER 20. THE JUMP SPARK OR HIGH TENSION COIL SYSTEM. ' 

Construction of High Tension System.—An induction coil,or jump spark coil con¬ 
sists of a core of soft iron wire over which are wound a few layers of insulated copper 
wire which is called the primary winding; in other words, this is our original low 
tension coil as shown in diagram 69. Over the primary winding are wound a great 
number of layers of exceedingly fine copper wire, insulated, called the secondary winding. 
When a current of electricity flowing through the primary winding from some source 
of electrical supply is suddenly stopped and then started again, it will cause a current of 
great pressure to flow in the secondary winding; although the two windings ai’e not con¬ 
nected, this current is induced or set up by the cause of the change in the magnetic 
















































































MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


41 


field. This induced current, set up in the secondary winding, is called the secondary 
current and flows in waves, there being a wave of current whenever the primary or 
battery current is stopped and started again by either the magnetic or mechanical 
vibrator. In diagram 69 the current leaves the positive pole of the battery, flows up and 
across the vibrating points, then around the primary winding around the core, then out 
across the timer which is making contact, then returns through the metal of the engine 
to the ground, and then back to the negative pole of the battery. The completing of this 
primary circuit causes the iron core to become magnetized, which attracts the trembler 
blade which separates the vibrating points, thus causing the primary circuit to stop 
flowing. This causes the iron core to demagnetize, which causes an induced current to 
rise in the secondary windirg and flow out to the center electrode of the spark plug; 
thus flowing down the firing pin of the spark plug it jumps the gap, grounds through the 
metal of the engine and thus returns over the ground back to where it started from. 
Thus a current flows around the secondary circuit every time the circuit is made or 
broken at the vibratirg point. The position of the spark plug in the cylinder can be 
placed as follows, over the center of the piston, over the exhaust valve, or over the 
inlet valve. The first position is not the best, as it is found that it too easily becomes 
foul; if screwed above the exhaust it will likely misfire. This is on account of the dead 
gases surrounding it. The correct position is over the inlet valve, as it will be kept 
cool by the inrush of fresh gases and it is in an atmosphere perfectly suited for ex¬ 
plosion. This has been found the most suitable place for the spark to appear, as it is 
the more perfectly cleaned part of the cylinder, and in the direct path of the fresh 
fases. The plug is usually placed over the inlet valve on T and L head cylinders. In 
overhead valve types the plugs are placed in the top or on the side of the cylinder; they 



PRIMARY VY/R£i T/MCR TO (0/1% 


tVBRATOR 


AVJ. SCREW 


corrects 

A L I. PRIMAA Y 

W'Resr 
(Alt CO A r' 

Busewf — 


"PA/MARr offcuirn emeu 
H£R£ BY RAPfO V/BRAT/MS 
-rfVMMY M,Cio»DAHV 
Cov/vccr H£«c 


pi?/MA&r c/ecwr, 


COKt. 

'S£CCWOAf?r C/ROJ/T 


^_ SeCONRARY CABLE? TV SPRRRPLC/OS 


W/REi Ail CP 

ffArre/nes 


Pi ton. w no T 

CYUNOER ON COM- 
PRSSiWN-AlOl 
A/Obi- FIRING 


iPARR 

PLUGS 


SCCONPARY CABLES TO 
5PARR PLUGS 


ROLLER 
ON NO! 
CONTACT 


FoMina 
j field . 


onouvo on 


CfOUVO P* TH OF .T ^7 

C/RCUfiT THRU. METAL OreNtoNFJ 


TAToU 


Diag» 70 Ford Dual or Double Ignition System us 


the 




























































42 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


are exposed to the full heat of the explosion, consequently in a high compression engine 
of this type a well-made plug must be used. Many of the overhead valve engines have 
the plugs in the side of the combustion chamber. 

CHAPTER 21. THE FOUR VIBRATING COIL SYSTEM OF IGNITION 

USED ON THE FORD. 

Dual System.—At Diagram 70 the illustration there will explain from the wiring 
connection from the battery or magneto through the entire primary circuit. In order 


‘Rod connects 
With SPARK 
LEVER. OK 
STEERIN' 

Wheel 



METAL BASE- 
PI 0RE-NON CON DUCT I NO 
MATERIAL 
ONTACT POLLR HUB 
ENOOP CAM SHAFT 


T-2-3-4 

BINDING POST OP 
'ONTACT SEGMENT 

ME.TAL. ROLLER. 


SPRING 

Pig 2—Roller type of 
contact commutator (four 
cylinder type as an exam¬ 
ple) 


Blag. # ?1 Commutator or timer Con¬ 
struction 

to clearly understand what the current travels through, place your pencil on the draw¬ 
ing at the positive pole of the battery or the insulated terminal of the magneto. Re¬ 
member now, and at all times, that there are certain necessary parts which always have 
to be in the primary circuit; as the current leaves the source, which can be either a 
mechanical generator or a chemical generator, it passes over the wire to the ignition 
switch. From the ignition switch it must go around the primary winding on the iron 
core; it must then go through the timer or commutator and return to where it started 
from. The commutator or timer is a mechanical switch which is generally driven on the 
end of the cam shaft, and is used to connect up the primary circuit at the instant the 
piston gets in firing position. As soon as the primary circuit is complete the trembler 
blade is pulled down, thus separating the platinum points, which, when together, form a 
part of the primary circuit. When broken for an instant causes the primary circuit to 
cease to flow, which causes a sudden change in the strength of the magnetic field, and 
this produces an induced current in the secondary winding, which flows out through the 
secondai'y cable to the spark plugs, there jumps the gap in the spark plug and then 
returns over the primary wire which is connected to the timer back to where the 
primary and secondary are connected together; there it returns into the secondary from 
whence it started. 

Commutator or Timer Construction.—Diagram 71 shows a very plain view of the 
commutator or timer which is used on the Ford. The metal contacts in the fiber hous¬ 
ings to which the wires from the coils are connected are called segments. There are as 











MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


48 


many segments in the timer or commutator as there are cylinders. These segments are 
placed certain distances apart, according to the number of cylinders. For instance, a 
two-cylinder commutator would have two contacts. These two segments would be 
placed 180 degrees apart. If a single cylinder engine, only one spark is necessary during 
two revolutions of the crank shaft, therefore the contact roller would revolve one half 
the speed of the crank shaft, and would be placed 360 degrees apart, or one contact 
segment. On a four-cylinder engine there would be four contacts, placed 90 degrees 
apart, as shown in Diagram 71. Because a contact roller revolves one half the speed 
of the crank shaft there would be four sparks during two revolutions of the cranlf 
shaft. If a six-cylinder engine, six impulses or contacts are necessary during two revo¬ 
lutions of the crank shaft; therefore, the roller contact would revolve one half speed 
of the crank shaft also. The contact segments would be placed 60 degrees apart; on an 
eight cylinder engine, the contact would be 45 degrees apart on a twelve cylinder engine. 
The segments are insulated in a fiber houisng which only prmits th primary circuit to be 
connected up when the metal roller is making contact with the segment. 

How the Commutator or Timer Helps Control the Speed.—The commutator or timer 
is connected with the spark lever on the steering wheel as shown in diagram 72. When 



Diag. # 72 Show how timer or commutator Control the 
appearance of the spark in the C 0 mbustion Chamber 


the spark lever is pushed forward the commutator is shifted forward so that the metal 
roller makes contact earlier with the contact segments. This is called advancing the 
spark. If the commutator is shifted back instead of forward, the contact is made 
later; this is called retarding the spark. There are two methods of advancing and 
retarding the spark; this is either done by the hand spark lever or it is automatically 
controlled by a governor. It is well to run with the spark lever as well forward or ad¬ 
vanced as possible, as it will tend to keep the speed of the engine up and consume less 
gasoline and create less heat. If the spark lever is too far advanced then the engine 
will pound, or knock, because the ignition will take place before the piston is over top 
dead center. The amount of advancing or retarding of the hand spark lever in order 
to get the best results, must be learned by actual practice. 





















































44 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


The Master Vibrator.—At Diagram 73 is illustrated a Master Vibrating Coil on a 
4-cylinder engine. The purpose of the master vibrator coil is to do the vibrating foi the 
other coil; for instance, quite often multiple cylinder coils with several vibrators cause 
considerable trouble from the sticking or welding together of the platinum points, caus¬ 
ing missing. Where a multiple unit coil is used a great deal of care must be exeicised 
to keep them in proper adjustment by placing a single wound master vibrator coil in 
series with the primary circuit and by short circuiting all of the vibrators in the 
coils the one master vibrator will do the work for the others. It will be noticed, however, 
the other coils are used for producing the high tension current; also note there is but 
one winding on the master vibrator coils; its purpose merely being that of vibrating and 
changing the stiength of the magnetic field in the other four coils. 



3*<4/t*A«lXVRr- VfvmYGKQvvPED/fif f-O"- 

Piag. # 73 A Master Vibrator coil on a four 
cylinder engine 


At diagram 73 it will be noted the firing order is 1-3-4-2. Number 1 cylinder i» 
now firing as coil c-i and the contact on the segment commutator number 1 are in 
operation. The next cylinder fire will be number 3. Note all the secondary wires are 
grounded on one end; this is usually done in the coil box; all connections being made to 
a binding post. A ground wire is then run to the frame of the engine from the binding 
post. 

CHAPTER 22. THE DISTRIBUTOR OR SYNCHRONOUS SYSTEM OF IGNITION. 

In the foregoing examples it will have been noted that the amount of wiring- 
required for motors having more than one cylinder becomes increasingly complicated. 
A system now generally used, known as the distributor system, very considerably 
simplifies the wiring, and at the same time more accurate timing of firing of the 
respective cylinders is obtained. 

At Diagram 74 one trembling coil only is necessary; this having the high tension 
terminal joined to the distributor which is a special form of rotating switch highly 
insulated which distributes the high tension current to the cylinders according to the 
firing order. The distributor arm and brush B rotate at the same speed as the commuta¬ 
tor roller contact maker and in perfect unison with it; that is to say, when the following 
low tension current is completed, the high tension current is completed likewise. The 

















































MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


45 


diagram should make the system clear; it being borne in mind that the distributor is 
rotating as well as the contact maker, and in perfect synchronism; or to state it more 



Blag,74}- A biglj tension distributor or synchro :cus system of ignition P—primary winding. S— 

•eOond&ry Note one end grounds to engine: usually grounded on the coil VS—-vibrator screw 

Fig 2—Note distributor and commutator are together The wiring db"-am shows' the two separated 
««rely to explain the action 


dearly, the roller in the commutator makes contact with the segment, at the same time 
the vibrating points vibrate, which causes an induced current from the secondary wind¬ 
ing; and the distributor brush at B is making contact with the segment in the distributor 
all at the same time. 

The secondary distributor is made in combination with the commutator, each with 
as many contacts as the engine has cylinders, ard the moving part of each attached 
to the same shaft that revolves. See figures 2 and 3 in diagram 74. The battery is con¬ 
nected to the single coil in the usual manner and runs from the primary winding of the 
coil to the segment on the commutator; from there to the roller through the metal 
of the engine over to the ground and returns back to the negative pole of the battery. 
Thus, when the commutator revolves and the roller makes contact with the segment, 
the current is passed through the one coil every time the contact is made. In a 
distributing system of this kind a wire is run from the secondary winding of the coil 
to the revolving or moving part of the distributor, and from there, when the distributor 
arm and brush makes contact with the segments, to which wires are fastened running 
to the spark plugs every time contact is made and the vibrator vibrates, the current 
lows from the secondary winding to the distributor and thus is distributed to the 
cylinders according to the firing order. The advantage of this system is that there is 
•nly one vibrator to keep in adjustment, and fewer parts; the disadvantage is that the 
coil has no rest, and the constant use tends to heat it, and destroy its insulation. The 
constant action of the vibrator is liable to burn the vibrating points and destroy them; 
therefore the modern ignition systems use a distributor system of a similar principle 
to the Delco and Atwater-Kent Systems. The vibrator is not used, the timer being 
•f slightly different construction, which obviates the necessity of the vibrator. ‘ 




f 
















































46 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


Open and Closed Circuit Principle.—The modern interrupter or contact breaker, 
in its simplest terms means a mechanical switch which is driven by the engine 

and is used to make and break the primary 
circuit at the time the spark is needed in the 
cylinder; or mechanical vibrators perform 
the same job that the trembler blade per¬ 
forms on the vibrating coil, and these 
mechanical vibrators are divided into two 
types; the vibrator in which the circuit of 
the primary winding of the coil is always 
open only when the arm, figure 2, diagram 
75, is raised, contact is made with Tungsten 
Points screw, C. This closes the circuit, 
but it is suddenly opened again, and is 
known as the open circuit principle. Figure 
3, diagram 75, the other type or system is 
that in which the circuit of the primary 
winding on coil is always closed. When the 
cam or interrupter D raises the arm B, the 
circuit is momentarily open, and suddenly 
closes again. This is called the closed cir¬ 
cuit principle. The action interrupts the 
current or flow suddenly, hence, it is called 
an interrupter. Both of these systems have 
a mechanical method of making and break¬ 
ing the primary circuit instead of the elec¬ 
trical method such as the vibrator; there¬ 
fore, a coil without a vibrator is used and 
a single spark is given at the plug gap in¬ 
stead of a succession of sparks. Both the 
open circuit and closed circuit systems accomplish the same purpose, which is to inter¬ 
rupt the flow of current in the primary winding in order to cause induced currents of 
high voltage to flow in the secondary winding, as previously explained. In the open 
circuit principle the contact must first be made before the current flow can be interrupted. 
This is made very rapidly, quicker than the eye can detect. In the closed circuit princi¬ 
ple the current is flowing in the primary and is broken or interrupted by the contact 
points being separated by the cams which run at cam shaft speed. The closed circuit’s 
advocates claim the advantage of perfect distributing of the high tension current to the 
cylinders, due to elimination of electrical and mechanical lag, whereas the open circuit 
advocates claim economy. 

Electrical Lag means that the spark will not occur in the same position as regards 
piston travel at any and all engine speed. With a very high speed the piston might 
have a tendency to travel past the point of ignition before the open circuit timer made 
an open contact, whereas, with the closed circuit principle it merely opens the contact. 

Mechanical Lag is eliminated much for the same reason, and the quicker and simpler 
the mechanism to interrupt the flow in the primary, the quicker the spark. For this 
reason some of the systems have been additionally improved by adding an automatic 
advance of the spark by a governor arrangement placed in the timer housing, so that 
the timer shaft will advance with the speed of the engine and cause the spark to occur 
as near the proper time as possible. 



Diag. # 75 Show the 
open and closed Cir 
cuit Mechanical 
Vibrators 












































MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


47 


In diagram 75A the governor is illustrated at figures 6 and 7, and is mounted directly 
under the timer. One arm of the governor, G-l, is attached to the upper part of the 
timer shaft, which is free to advance with the action of the governor. The other arm 
of the governor automatically advances the time of the spark as the speed of the engine 
increases by centrifugal action of governor G W as shown. Note position of the ends 
of the timer shaft A retarded, figure 6, and advanced in figure 7. 



Diagram 75-A. Automatic Spark Control Governor. 


The Resistant Unit—the Purpose.—When the closed circuit type of ignition is used, 
some method must be employed to disconnect the primary circuit if the switch is left 
on accidentally when the engine is not nxnning. Resistant units and thermostats are 
therefore employed. The resistant unit used with the Delco System, which is an open 
circuit principle, is for the purpose of obtaining a more uniform current. It consists 
of a coil of resistance wire wound on a porcelain spool, as shown at diagram 76. Under 
ordinary conditions it remains cool and offei’s little l'esistance to the passage of current. 
If, for any l’eason, the ignition circuit remains closed for any considerable length of 
time, the current passing through the coil heats the resistant wire, inci’easing its 
resistance to a point where very little current passes, and insuring against a waste of 
current from the battery and damage to the ignition coil and timer contact. This 
insures uniform cui’rent through the primary winding. 


The Thermostat Circuit Breaker.—A 

thermostat circuit breaker mechanism is 
shown in diagram 77. The thermostat is in¬ 
closed within the ignition switch; its pur¬ 
pose is to open the circuit should the switch 
be left on when the engine is not running. 
The thermostat consists of a blade, T, which 
heats when the cii'cuit passes through it 
from thirty seconds to four minutes without 
interruption, and is bent downward, making 
contact with contact L. This completes an 
electrical circuit which enei'gizes the magnet 
M, causing the ai*m K to operate like the 
clapper in an electric bell. This arm strikes against a plate which releases whichever 
of the two buttons in the switch may be depressed or on. Thermostats may be said to 
act from thirty seconds to four minutes. 

The Depolarizing Switch is also called a pole changing switch, used in connection 
with ignition systems; is provided for the purpose of keeping the contact point on timer 


JhuotLcoo F/ron 
GMRtTM.faObHC _ 

Fnon JtWcH Cohhcct 

atiUb/rmtAL 


l ig «J 


Thc WifraTbTuac TamtNuu nun 
t Not Bi fStffUCD 

, INC TeftVML CoMKCTS Til DlOTNiSUTOft 
HiCHTeffUMWmTd 
’'UNnffOrtoTmguTOR 



ffmwrr mom. 
Secwaw mom 
Cowrcat 


Con O/tACHtf rtosrOc 
GlTOUNOU). 


Diag. 76 The 
sistant Unit 


Rs- 















































4 8 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 




SWITCH 

CONTACTS 


IGNITION SWITCH 


QHXA6TNG 

HAKKTC 


An automatic thermostat «n 
the Connecticut system breaks 
the circuit In the event that 
the switch Is left In the •'on" 
position with the motor Idle* 
The light switch and dimmer 
are housed at the right 


. THD2WOSTA.T 


THCCM05TATIC 
CIRCUIT £>RXAKiy 



Diag. 77 A Thermostat Cir¬ 
cuit Brea leer 


clean. When direct current is used, it has a tendency to burn and pit the points, whereas 
an alternating current is much easier on the points; therefore, to alternate the flow 
of current from N to S and S to N, or positive to negative and negative to positive, is 
the principle of this style switch. As already stated, direct current is used with all 
battery systems; therefore, a steady flow in one direction has a tendency to deposit the 



Diag, 76 The Depolarizing 
Switch 

metal from one point to the other, hut by changing this flow of current occasionally the 
deposits will be put back to the other point again. This is similar to electroplating. 
Note the action of the polarity switch in diagram 78. The current, D, is now flowing 
negatively; A is flowing positively. By turning the switch one quarter turn the poles 
are changed; A will become negative and B will become positive. This change is made 
occasionally when running and has a tendency to keep contact points clean. 













































































MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


49 


Parts of a Modern Battery and Coil System of Ignition.—The parts of this system 
consist of a storage battery, ignition coil, timer, distributor, spark plugs, and 
accessary wires to complete the circuit. Diagram 79 illustrates the theory upon which 
the battery ignition system is operated. The distributor is usually placed over tha 
lamer. First, note the timer shaft, which is driven from the cam shaft usually by a 


1M50LAT10 



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CRCUSP 


Diag.79 Diagram illustrating the theory upon 
which battery ignition systems operate. 


spiral tooth gear and at cam shaft speed. The distributor brush is connected to the 
upper end of this shaft and as it revolves makes contact with the spark plug terminals. 
Note center contact on gear of brush connecting with the secondary wire from the coil. 
The timer is that part containing the interrupter or contact breaker mechanism and is 
placed below the distributor. 

This mechanism simply makes and then breaks the flow of current in the primary 
circuit. In this modern battery and coil system of ignition a primary current of six 
volts leaves the positive of the storage battery and flows up around the primary winding 
on the iron core, then over and across the breaker points or interrupter points, and then 
returns through the metal of the engine to the ground and back into the negative pole 
of the battery. This causes the iron core to become magnetized, which causes the 
secondary winding to be in a magnetic field. One end of the secondary winding runs 
over to the center of the distributor and fastens to a brush which is connected up to the 
distributor arm. The other end is either fastened to the primary winding or to a metal 
strip on the outside of the coil when the coil is installed you must be sure this metal 
terminal makes contact with the metal of the engine, so the high tension current will 
have a complete circuit. So remember A CURRENT OF ELECTRICITY MUSI AL¬ 
WAYS RETURN TO WHERE IT STARTS FROM. When the distributor arm is male- 


































) 


SO _MODERN ELECTRICAL MOTOR CAR EQUIPMENT 

mg contact with a terminal or segment in the distributor housing it produces a complete 
circuit of the secondary winding, except the small gap in the spark plug, which is 
located in the combustion chamber. When the breaker points open or close suddenly it 
causes a change in the magnetic field, which causes an induced current of from ten to 
twenty thousand volts to arise in the secondary winding, and as one of the fundamental 
principles of electricity is that YOU HAVE ALWAYS GOT A COMPLETE CIRCUIT 
AS LONG AS THE VOLTAGE IS HIGH ENOUGH TO FORCE THE CURRENT 
THROUGH THE RESISTANCE; in this case the pressure of the current is greater than 
the resistance and therefore the current through the high tension circuit is completed, 
and, as passing through the gap in the spark plug, an arc is produced which is utilized 
to set the mixture in the engine cylinders on fire. 



- "*<4© ^ Timer Case and 

Condenser jr/m/np Case Couer Interrupter Assembly 

Di3g»®0 Partially Dismantled Four-Cylinder Magneto, Showing Important Parts of Current-Producing and 

Distributing Elements. 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


51 



\ 




































52 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


CHAPTER 23. HIGH TENSION MAGNETOS. 

The important parts of a four-cylinder form of high tension magneto are shown 
at Diagram 80,which is a view of a practically dismantled device. The armature assembly 
and one end of the end plates on which it is supported, are shown at the extreme left. 
Attached to the end of the armature shaft are the distributor driving pinion gear and the 
ebonite spool which carries the collector rings. The timer case and interrupter case 
and interrupter assembly are shown at the extreme right. Above it the distributor 
case is clearly shown. When the device is assembled the ends of the armature shaft pro¬ 
trude through the housing at the magnet assembly which is shown in the center of the 
group with the end plate which carries the distributor gear and disc and one end of the 
armature plate. The distributor gear serves to drive a hard rubber plate in which the 
distributor segments are embedded. When the distributor case is screwed in place, the 
carbon brushes which are spaced around the interior of the distributor case collect 
current from the revolving distributor segment and lead it to the spark plug by suitable 
cables which run from the terminal at the top of the distributor casing. There are two 
kinds of magnetos; one is termed the high tension system, in which a current of high 
voltage is delivered directly from the armature; the other is known as the low tension 
magneto. The current produced by the armature winding of the low tension magneto 
must be stepped-up, or increased in value before it is delivered to the spark plug, by an 
, induction coil similar in construction to that needed in a battery ignition system. The 
high tension current is produced by means of a secondary winding on the armature itself 
and the whole apparatus is much more compact, and simpler to install than those which 
need a separate transformer coil. The simplified wiring system of a high tension mag¬ 
neto is shown at Diagram 81. The armature carries two windings, one irdicated by the 
heavier lines at the bottom called the primary; the other composed of finer wire is 
known as the secondary. One end of the primary winding is grounded or fastened 
to the metal of the armature; the other is joined to the fixed contact screw of the 



Biag, # 81 A simplified wiring system 
of a High Tension Magneto 



















































MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


5S 


contact breaker. This end is also joined to one end of the secondary winding, ard the 
free end of the secondary winding is attached to the collecting ring carried by the 
ebonite spool. When the armature revolves between th pole pieces of the magnet an 
induced current will arise in the primary winding evry time the polarity in the armature 
is changed, thus causing a primary current to flow around the primaiy winding. This 
current flowing around the primary winding causes the iron core to become a magnet 
which causes the secondary winding to be in a magnetic field. When the contact points- 
separate, a current is induced in the secondary winding and is delivered to the center 
terminal of the distributor disc by the carbon brush which bears against the collecting 
ring. The various segments of the distributor are connected to the spark plug in the 
cylinder and every time the contact points separate a spark will be produced at one of 
the spark plugs because the revolving distributor brush will be in contact with one of 
the distributor segments when the contact breaker opens. 

Safety Spark Gap Principle.—In Diagram 81 is illustrated the Safety Spark Gap. 
This is practically a safety valve for the high tension current. If, for example, a wire 
becomes detached from the spark plugs or from the distributor so that the ordinary 
path of high tension current was barred, there would be considerable danger of the 
current forcing a circuit through the insulation of the armature and thus doing very 
considerable damage, were it not given some easier escape as provided by the safety gap. 

The Safety Spark Gap Construction.—It consists of a little chamber formed on- 
top of the armature cover plate with a top of insulated material. The gap between 
the two terminals of the safety spark gap is longer than the gap between the spark 
plug, and ordinarily no spark will pass between these terminals; but if, owing to the 
conditions already mentioned, no spark can pass at the regular spark plug and the 
electromotive force in the secondaiy winding attains an abnormal value, a discharge will 
occur at the safety spark gap, thereby preventing the secondary current from rising 
still higher and burning out the windings. 

Timing a Magneto Within Itself.—Timing a magneto within itself is to arrange the 
revolving distributor segment in the center of the carbon brush of the distributor case, 
then advance the spark half way, then without the distributor gear in mesh with the 
distributor drive pinion revolve the armature until breaker points are just ready to open ; 
mesh the distributor drive pinion with the distributor gear and the magneto is in time 
with itself. 

* 

The Bosch NU4.—At diagram 82 the type NU4 Bosch magneto differs from the usual 
type of magneto in that the distinct gear driven distributor common to other types ha& 
been eliminated, and in its stead is a double slipring combining the function of current 
collector and distributor; otherwise it is about the same as any other form of magneto-. 
The spark occurs in two cylinders at ore time with this system, but one of the cylinders 
in which the spark occurs is on exhaust stroke; therefore the spark does no harm. The 
interrupter contact point in the full retarded position should open not later than top dead 
center of the compression stroke and the surplus spark always occur near the end of the 
exhaust stroke and never during the inlet stroke. In any four-cylinder, four-stroke cycle- 
engine, regardless of firing order, when cylinder number 1 is nearing the end of com¬ 
pression stroke, cylinder number 4 is reaching the end of exhaust stroke, and vice versa. 

Similar conditions apply also to cylinder numbers 2 and 3. Diagram 82,illustrates 
very clearly the different parts of the Bosch NU-4 and how they functionize. The brush 
when making contact with metal strip in collector ring, connects the high tension cur¬ 
rent and carries it to the spark plug. Note the connections from the ring to the plug. 
When brushes 2 and 3 are making contact, follow the circuit in figure 6 and note the 
arrow points. Now if the piston makes another stroke of 180 degrees travel, the arma- 

s 





54 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 




0/STR/&- 
(MO* AMD 
RPNE END 


TO 

SWtTCH SHAFT 


t NTERUPTQR 
END 


[FoT] 


rot lector t4 

R /MGHNSroe 




CARQOJV BRUSHES 
ETA l SEGMENTS 
'OH HO 2 SUP PiHG 

SECONDARY WINDING 

or— 4 


\M1 



THE TWO METAL SEG-VNSUk* TE&J ADJT SCREW 
Mf/VTS ARE SET /S0° wa/t /RuPTE R ARM 
APART C ARE IN grouhoeo 

sulated tron Eac* cams /go 9 apart 

OTHER 




aRma turc AMO SL/F 

ring mas turned 

ISO* a male REVOLUTION 
SAMf as ENG/A/E CRAM A 


MOTE 
PLOW OF CURRENT 


Dtag. #82 The Bosch NU4 
A two-point system 


type of High Tension Magneto 


ture will turn 180, or half a revolution also, as it runs at engine speed in four-cylinder 
four-stroke cycle engine; therefore the contact or rings will turn 180 degrees or half a 
revolution and cylinders four and one will fire as in figure 7. 

Timing the NU4 Magneto With Engine.—With the average engine the best result 
is obtained by connecting the magneto so that its interrupter housing is in full retarded 
position and the platinum interrupter screws or points are just about to sepai'ate when 
piston of number 1 cylinder is exactly on top dead center of the compression stroke; at 
the same time the metal of the slip ring should be in contact with the brush marked 1 
in each of the brush holders, and this can be observed by removing one of the holders. 
The installation is complete by connecting one of the brushes marked 1 with cylinder 
number 1 and the others with cylinder number 4 and the two remaining brushes marked 
2 and 3 with cylinder numbers 2 and 3. It is important to note that the type NU4, 
driven as it should be at engine speed, produces a surplus spark in each cylinder 360 
degrees behind the effective or power spark, and in coupling the magneto to the engine 
it must be timed so that the surplus spark occurs dui'ing the exhaust stroke and not 
after the inlet valve has commenced to open. 


CHAPTER 24. THE DIXIE HIGH TENSION MAGNETO. 

The Mason Principle on Which the Dixon Operates is shown in diagram 83, figure 4. 
The magnets have two rotating polar extremities, N, S, which are always of the same 
polarity, never reversing. These poles are in practical contact with the inner cheeks 
of the permanent magnet M, all air gaps being eliminated; together with the U-shaped 
magnets they form a magnet with rotating ends positioned at right angles to the 
rotating poles or ends is a field constructor consisting of laminated pole pieces F and O, 
carrying across their top the laminated core C, carrying the winding W. When N is 























































































MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


55- 



Dleg. # 83 Dixie Induction tyge of High Tension 
Magneto* its principle, of operation 


opposite F the flux or magnetic lines of force flow through the core O to F; see 
figure 6. This action causes the laminated core with the winding wound on it 
to become magnetized, and as it revolves the polarity is changed, causing an induced 
current to appear in the primary winding, which flows out across the breaker 
points and back to where it started from. That causes the secondary winding to be in a 
magnetic field produced by the primary circuit, and when the breaker points break the 
primary circuit it causes the magnetic field to cease causing a high voltage current to 
appear in the secondary winding- which is distributed to the spark plugs according to the 
way the engine fires. 

Diagram 83 represents a rotating pole occupying a midway position between that 
shown in figures 5 and 6. Here the magnetic field pieces, F and O, are magnetically short 
circuited as if it were thereby completely cleaning all straying lines of force out of the 
core C. 


Now the first great difference between the Dixie and the Armature type is in the 
fact that the rotating poles in the Dixie do not reverse their polarity at any time, conse¬ 
quently the lag due to the magnetic reluctance in this part is eliminated. This partly 
accounts for the high efficiency of the Dixie at high speed for multiple cylinder 
engines. In the Dixie the windings are actually never in the field. The line of force 
is shot through them and produces a snappy spark of peculiar and highly efficient 
igniting power owing to the quick break and absolute reverse of the flow of magnetic 
lines at each revolution. The Dixie rotating element consists of two pieces of cast 
iron with a piece of brass between them with no moving wire connections, brushes, 
laminations, condensers or other parts, just two pieces of iron. 

In the Dixie the core of the coil, A, dia¬ 
gram 84, is stationary, and the inner end, G, 
of the primary winding, P, is grounded on the 
core. Q indicates the metal frame of the ma¬ 
chine which is put together with screws so 
there are no brushes or sliding contacts. The 
condenser, R, in the Dixie is positioned im¬ 
mediately above the coil and is readily re¬ 
movable, it being only necessary to take out 
two screws. This condenser does not revolve 
as in the armature type. The terminals, D,. 
are screwed on the head of the coil and the 
wires, Z, connect directly to the contact, Y, of 
the breaker; the breaker contacts in the Dixie 
are stationary and do not revolve as the armature type. To adjust the contact points, 
X and Y, of the Dixie the points are readily adjusted while the magneto is running, 
therefore the intensity of the spark produced may be actually seen while the screws 
















































56 


MODERN ELECTRICAL MOTOR C AR EQUIPMENT 

are being manipulated. The breaker point gap is set twenty thousandths of an inch 
or half way between a sixty-fourth and a thirty-second; and the spark plug gap twenty- 
five thousandths of an inch. 

CHAPTER 25. MAGNETO DRIVING METHODS. 

The magneto is usually placed along the side of the engine, mounted on a separate 
base provided for it. The base of the magneto is usually made of brass or aluminum, 
as brass or aluminum will not become magnetized; therefore, the magnetism is con¬ 
fined to the magnets; otherwise they would soon lose their magnetism. The magneto 
armature shaft is usually driven by gears, also silent chains. Loss, motion, and play 
should be eliminated in the magneto drive, and it is always advisable to drive the 
magneto through.gears. The magneto may be driven by chains and sprocket if gears 
•cannot be fitted, but the arrangement should be such that the chain will run with as 
little slack as possible, and at the same time not place undue side strain on the armature 
bearing. The necessity for preventing slipping prohibits driving the magneto by belt or 
by friction. On silent chain drives there is usually an idler or some means provided to 
take up the slack in the chain. The armature must be driven at a fixed speed because 
the armature must be in a vertical position, and interrupter points just breaking when 
the piston is in the correct position to receive the spark. In regular operation the correct 
position for the piston to receive the spark is just at the instant before it gets at the 
end of a compression stroke. Diagram 85 illustrates how the armature is therefore 
«et by meshing the gears in relation to the gears on the crank shaft. 

Means of Advancing and Retarding of Spark.—The meaning of advance of spark is 
to cause a spark to occur earlier before the piston is at the top of the compression stroke. 
The meaning of retard of spark is to cause spark to occur later on engines that are 

• cranked by hand; the spark is usually set retarded after top, so that there will be no 

• danger of a kick back. 

Control of Spark.—As the spark occurs only when the primary circuit is broken 
by the opening or closing of the platinum contact points, the timing of the spark can 



Diag. £ 85 Shows how spark is em¬ 
broiled. on Magneto 


therefore be controlled by having these points to open sooner or later. This is ac¬ 
complished by the annular movement of the timing lever. This movement is a timing 
arrangement of about 35 degrees. See Diagram 85. The spark is fully retarded when 
the timing lever, or sometimes called spark lever, is pushed as far as possible in the 











MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


57 


direction of rotation of the armature and is advanced when pushed in the opposite 
direction. If cranking by hand, the spark must occur after the end of compression 
stroke, or else engine may kick back. If started by some form of self starter, it is then 
possible to start with slightly more advance than by starting by hand, because the self 
starter turns the engine crank faster. 

Magneto Speed.—A high tension magneto of standard construction produces a high 
tension or jump spark current, this current being generated in the windings of the 
magneto without the use of a separate induction coil. Two ignition sparks are pro¬ 
duced during each revolution of the armature in the usual type, and these are trans¬ 
mitted to the proper cylinders by means of the high tension distributor which is integral 
with the magneto. Once during each half revolution of the armature the primary 
circuit is broken and the abrupt interruption of the primary current results in the pro¬ 
duction of the high tension current in' the secondary winding. The variation of ignition 
timing is effected on the magneto itself. The arrangement permits the interruption 



Diag.86 —Magneto Drive Methods.. Magneto Armature Speed. 


which is controlled by the spark lever as was explained in diagram 85 of the primary 
current to occur earlier or later in the revolution. On a four-cylinder engine four sparks 
are required during two revolutions of the crank shaft. The magneto gives two sparks 
or impulses to one revolution of the armature; therefore it would be geared to drive 
at the same speed as the crank shaft. See diagram 86. 

On a six-cylinder engine six sparks are required during two revolutions of the 
crank shaft, therefore the armature would revolve one turn and half of another turn, 
makirg three sparks while the crank shaft made one turn; therefore, on two revolutions 
of the crank shaft the armature would make three revolutions, thus producing six 
sparks. The distributor, however, on both the four- and six-cylinder engines would 
revolve one half the speed of the crank shaft as the distributor arm would make one 
revolution to two revolutions of the crank shaft. By referring to diagram 86 note the 
cam C on the interrupter with projections 180 degrees, or one half of a revolution apart. 
This causes an interruption of current every half revolution of the armature. 












































































58 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


CHAPTER 26. DRIVING METHODS OF DISTRIBUTOR AND TIMER 

IGNITION SYSTEMS. 

In this system, shown at diagram 87, are combined the distribution and timer, to- 
gether with ignition coil spark plugs, and wiring, all of which constitute the 
ignition system. The source of supply can be from storage battery, dry cells, or gen¬ 



erator. The distributor and timer are mounted on the end of the shaft, while the 
other end carries a small beveled gear which meshes into a small gear on the cam 
shaft. Now it must be thoroughly understood that in a system of this kind where 
only one coil is used, and we have a distributor which is a mechanical switch, and is 
driven by the engine and is called upon to deliver the high tension current to the 
cylinders according to the firing order, and a timer, or breaker points which are called 
upon to either make or break the primary circuit at the time the spark is needed in the 
cylinder—now when these are being installed upon the engine they must be arranged to 
perform their duty at the right time. The interrupter points should just be breaking 
when the distributor arm is making contact with the segment, with the timer housing 
in a full retarded position, and the bevel gear on the end of the shaft which drives the 
timer and distributor must be connected with the gear on the cam shaft when the piston 
is at the end of the compression stroke, and as the interrupter points are just ready to 
break the circuit the gear should then be meshed. In timing any ignition system with 
an engine the means of controlling spark, and being able to have it occur at the right 
time, is accomplished by either making or breaking the primary circuit. This is ac¬ 
complished by either making or breaking the primary circuit. 

When a mechanical vibrator is used, as on a magneto, or in battery ignition system, 
the piston on number 1 cylinder should be put in firing position, or have the piston up 
as far as it will go, on compression stroke, then revolve the armature in the magneto, or 
turn shaft which drives timer and distributor with gear on lower end disengaged until 
the points are just opening with the interrupter housing in retarded position, then con¬ 
nect up the magneto with engine and magneto is in proper time with engine, or engage 
































































MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


59 


gear on end of timer and distributor shaft and ignition is in time. On a Ford system 
where the vibrating coils are used, get number 1 cylinder in firing position, or on com¬ 
pression stroke, dead center, then with the timer housing in retarded position, arrange 
the roller which is fastened on the end of the cam shaft so it is just beginning to make 
contact with one of the segments in the timer case, and the ignition system is then in 
time. 


CHAPTER 27. TIMING THE MAGNETO WITH THE ENGINE. 

Diagram 88 illustrates very clearly how everything should be arranged; first, placa 
number 1 piston on top of compression stroke. To do this on a four- or six-cylinder 
engine, turn the crank shaft the way it should revolve until the exhaust valve on number 



4 or 6 cylinder opens and closes. This puts number 1 on compression stroke dead 
center. Second, retard the breaker box, also called interrupter housing, F, by turning it in 
the direction of the rotation of armature shaft as far as it will go. Third, turn 
armature in direction of rotation until the distributor arm, D A, is on segment S of 
number 1 spark plug cable connection; then turn armature one way or the other slightly 
until interrupter arm, A, is just starting to separate the platinum point connections 
P with K, which of course is caused by the cam action as shown. Fifth, couple magneto 































































60 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


connected. In this instance, by looking at the distributor connections and noting di¬ 
rection the distributor arm turns, the firing order would be 1-3-4-2. In some instances 
the piston is placed, say Vs of an inch down after center of compression stroke, witk 
breaker box retarded, then this would not permit advancing spark so far ahead of stroke. 
This is usually done on slow speed engines and where very slow running or idling is 
desired, as trucks and tractor engines. The armature turns in opposite direction to 
distributor; therefore always note direction distributor turns before connecting cables 
to plug. To tell how an engine fires watch the exhaust valve open and close in rotation, 
starting with number 1 cylinder. 

CHAPTER 2« A DIGEST OF TROUBLES: CAUSE AND REMEDIES OF THE 

IGNITION SYSTEM. 

Half the ability to make an adjustment or repair is the ability to discover its 
necessity. Always remember when diagnosing troubles, that there are three essentials 
necessary before an engire will run; first, gasoline: second, compression; third, spark. 
In dealing with engine trouble, always try and find out the possible cause of a trouble 
before starting to adjust something that does not need adjusting. An adjustment should 
never be changed without a knowledge of why the change is made, the effects the 
change should have, and how to restore the mechanism to its original adjustment. After 
you have gone carefully over the engine and find that the fuel system is operating 
properly, and that your compression is good, then you can look for the following 
ignition troubles. 

Engine Fails to Start.—Lack of ignition current; if battery ignition, see if battery 
is too strong; remove one of the spark plug wires and hold it about three eighths of 
an inch away from the plug and terminal and see if the spark jumps the gap when 
the engine is cranked. Next, examine spark plugs. They may have become fouled 
from over-lubricating; or, if they have been considerably used, the points may be 
burned and corroded. If water has been splashed on the engine when it was hot, the 
porcelain of the plug may be cracked. See that the spark points are perfectly clean, 
and that the gap does not exceed one thirty-second of an inch for coil ignition, or one 
sixty-fourth of an inch for magneto ignition. 

Engine Starts, but Misses.—This is generally caused from foul spark plugs, gap 
improperly adjusted, or from a weak coil. 

Engine Runs Regularly for a Few Minutes and Then Stops.—Battery may be weak; 
ignition may be retarded too much; if there are two systems of ignition, try the other 
one. 


Engine Stops Suddenly.—Loose wires; short circuit; loose wire connection; weak 
battery; points of interrupter may be closed by pitting; a sudden stop is almost always 
due to ignition trouble. - 

Engine Stops Slowly with Misfiring.—Battery exhausted; plugs foul through over¬ 
lubrication. 

Engine Loops or Loads Up.—The spark may be set too far advanced; if this is the 
case, looping is likely to occur when spark is fully retarded; therefore, test the time 
of ignition. 

Engine Misses Explosion.—Defective or dirty spark plugs. With the engine running 
idle, short circuit the spark plugs one at a time by touching a screw driver from the 
metal of the cylinder to the terminal of the plug; this prevents the plug from firing, 
and when one is short circuited that makes no difference in the running of the engine' 
you have probably located the plug at fault. If the spark plug wire is properly examined 





MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


61 


and no loose connections or short circuits can be located, the trouble is the defective 
plug. 

Engine Misses on High Speed.—Weak battery, if 'coil and battery ignition. If the 
engine misses at high speed but not on low or on a hard pull, then it is evident the 
spark plugs are O. K. The points on a magnetic or rpechanical vibrator may need 
adjustment. A word of explanation on this. The engine may fire all right at low speed 
because the speed is slow enough, and the contact is long enough to allow the coil to 
build up. At high speed the contact is too shoi-t, consequently a slight turn of the con¬ 
tact screw is-needed. The coil may be defective; that is, the vibrator points sticking. 
This is frequently the cause of missing of explosion. The points burn together. The 
cause of this is the direct current flowing in one direction continuously. Another cause 
is that of using too much pressure or voltage; for instance, coils are wound for six 
volts. If each dry cell gives 1% volts when working, and five cells are used, the coils 
points do very nicely. If, however, eight cells are used, the excess pressure is more 
than the condenser in coil can take care of; results, excessive sparking at platinum 
points on the vibrator and screw. 

The contact points should be inspected occasionally to see that they are clean and 
flat, and also that the maximum gap between the points is according to the gauge on 
the special adjusting wrench, or about 12 to 14 thousandths or one sixty-fourth of an 
inch. 

Engine Misses on Low Speed.—If magneto ignition the cause may be due to the 
slow speed of magneto, and weak current generated. Tiy advancing the spark more; 
also examine the interrtipter points; examine spark plug points; if missing still occurs, 
then there are two other points to consider, loose connections or a broken down coil. 
A spark plug may be foul; it has been known that a bad plug will not cause missing 
at all speeds. 

Engine Misses at All Speeds.—Defective spark plugs, loose connections, weak 
battery, loose switch parts, broken wire, slight short circuit. 

Engine Does Not Deliver Full Power.—Timing of ignition may be wrong. Set too 
far retarded or too far advanced, weak ignition, defects in distributor. 

Engine Overheats.—Running on retarded spark invariably causes heating. The 
spark lever should be raised up or advanced as far as possible at all times without 
causing the engine to knock. 

Engine Knocks.—The most common knock is the ignition knock, caused by too much 
advance of spark. This causes the mixture to be set on fire too early, causing the gas 
to be set on fire, and the pressure from the explosion forces the piston back instead 
of letting it get past top dead center and forcing it down on power stroke. 

Engine Will Not Stop When Switched Off.—If firing is regular, the switch is de¬ 
fective. If firing is irregular, pre-ignition is the cause, caused by poor oil or carbon 
deposits in the combustion chamber which harden and become red hot, hence resulting 
in preignition. 

Engine Back Fires in Muffler.—Usually caused when coasting with spark off and 
retarded, suddenly throwing on the switch, thereby firing charges and which have entered 
muffler unfired. 

Overheating of Exhaust Pipe and Muffler.—Very late ignition will not give enough 
time to permit the charge to burn before the exhaust valve opens. 

Engine Makes an Unusual Hissing Noise.—Spark plug porcelain broken; spark plugs 
sot tighly screwed into cylinder. 



Wall Bracket Lamp 


62 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 



Diag. # 89 Show a Motor Car completely lighted with Electricity 



















































































MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


AS 

CHAPTER 29. LIGHTING THE MOTOR CAR BY ELECTRICITY. 

Electricity has many advantages as a lighting medium, and all those which make it 
so desirable for domestic use are supplemented by other features which specially adapt 
it to motor car service. The convenience and cleanliness of the lamps, the fact that 
the light is not affected by the speed, character of the road surface, or wind, and that 
it remains of uniform brilliancy as long as current of proper strength is supplied, are 
some of its advantages. The ease with which the lights may be turned on or off by 
merely operating a switch or pressing a button is a feature of merit, and that no skill 
is required to obtain proper results makes the electric current entirely suitable as an 
illuminating agent for motor cars. Diagram 89 shows a motor car fully equipped lighting 
system with a chemical generator for current production. The wiring is very simple. 
The current flows from one wire of the positive main current supply wire out to the 
switch; when the switch is closed it flows on and through the light and returns to 
where it started from. It does the same when all the circuits are closed by the different 
switches. When the storage battery runs down it must be charged from some outside 
source. The most important component of modem lighting systems is the incandescent 
light in which a conductor or filament is heated because it offers a high resistance to 
the' passage of electric current. To prevent a rapid oxidation or burning away of the 
incandescent conductor it is placed in a glass globe from which practically all air has 
been taken out by an air pump; this forming the familiar incandescent bulb of commerce. 

As the filament is heated by the current flow, no air is 
needed to maintain combustion, as is necessary when in¬ 
flammable substances are burned to obtain light. The 
normal life of an incandescent lamp filament is from one 
thousand to two thousand working hours. This filament 
is made of carbonizing a special form of cotton thread; the 
ends of the carbonized thread are attached to platinum 
wire which are sealed into the glass balls of the bulb 
and which make contact, one with the base or socket, 
and the other with its rim, these being the electrodes 
through which the current enters and leaves the lamp as 
shown in Diagram 90. 

At Diagram 91 instead of taking off the storage battery or charging it from some 
outside source, we have a dynamo connected up with the engine which produces a direct 
current suitable to keep the storage battery charged. You will observe four switches 
at diagram 91. Number 1 switch is in the circuit between the dynamo and storage 
battery; it is called a cut-out relay or magnetic switch. 

CHAPTER 30. CUT OUT RELAY. 

Diagram 92 illustrates an automatic cut out switch A. As shown it is placed in the 
circuit between the generator and storage battery. This device automatically connects 
the generator to the lighting system and battery when the engine is running at say 
approximately seven to ten miles per hour, car speed or over, and charges the battery 
and supplies current for lights and ignition. When running at less speed the switch dis¬ 
connects the generator from the battery and lighting circuit, and the battery then is 
called upon to supply the current. The principle of the cpt out relay is very simple, 
and easy to understand. When the engine is not running the platinum points at V3, 
diagram 92, are open, and if the lights are needed the current must be supplied from 
the battery. The spring V2 keeps the points separated so the storage battery cannot 
discharge through the generator and soon exhaust battery. When the engine is started, 
the generator, which is connected with the engine, begins to generate as soon as the 
engine gets to making three or four hundred revolutions per minute or more; a current 
of sufficient strength is generated and flows out and around the shuit circuit and wind- 



Diftg *90 The in¬ 
candescent lamp 









64 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 



-iS^fSlWirlng Diagram ©g Og&tlng Dynamo, OistlBniEg the Connecitions 
of Generator. Storage Battery and SwiteSje®. 

ing at P, which is wound around the iron core, which causes it to become an electro-mag¬ 
net and remains a magnet as long as the current flows from the generator. Thus the 
iron core becomes a magnet and it attracts the blade VI and draws it towards it. 
This closes the points V3, and allows the main current to flow from generator up to the 



Dl3o 14 ^ ^ the automatic magnetic cut out, opens 
the circuit between battery and generator when the 
generator is running slow or engine is stopped, also 
referred to as the “vibrator type” of cut out. 

trembler blade VI, across the points at V8 and around the winding at V and over te 
storage battery and lights and returns to where it started. As soon as the generator 
stops putting out a current and no current flows around th° 'windings on the iron core 
it ceases to be a magnet. The spring V2 holds the blade Vl away from the iron core, 
ihus separating the points at V3, thus opening the circuit between battery and generator. 











































































MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


65 


CHAPTER 31. THE AMPERE METER. 

Purpose of Ampere Meter.—It is provided as a signal for the operator; it indicates 
when the dynamo charges battery and at what rate, as shown in figure 1, diagram 93. 
It also indicates the rate of discharge from battery to lamps; it shows whether or not 
the system is working properly. When the battery is neither charging nor discharging 
the pointers should indicate O. The ammeter is placed in series with the circuit as 
shown in diagram 92 at V4. 

The Principle v4 Cons true lion of the Commercial Ammeter and Volt Meter is shown 
at figure 2, diagram 93. The coil C is pivoted on jewel bearings and is held at its zero 
position by a spiral spring, P. When a current flows through the instrument, were it 
not for the spring, P, the coil would turn through about 120 degrees or until its mrth 



Biage # 93, Construction of tne 
Commercial Arnmeter 


pole came opposite the south pole of the magnet. This zero position of the coil is 
chosen because it enables the scale divisions to be nearly equal. The shunt coil, R, is 
of practically negligible resistance. The volt meter differs from the ammeter only in 
that the coil, R, is in series with C and is of high resistance. The same instrument may 
have its range changed or may even be used interchangeably as an ammeter or a volt 
meter by suitably changing the coil, R. 



CHAPTER 32. REGULATION OF OUTPUT OF GENERATOR. 

In a dynamo the voltage increases with speed. The dynamo begins to charge the 
battery at about seven to ten miles per hour, but it is also desirable to charge a 
battery and supply current for lights at a higher speed. As the voltage increases with 














@6 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


the speed then the lights would be burnt out, and generator would be injured by ex¬ 
cessive sparking at commutator, and an excessive amount of current would flow to the 
battery; therefore, some form of regulation must be used to keep the voltage or 
quantity of current constant at a high speed. We will first illustrate and discuss a 
mechanical governor which controls the speed of the armature to a fixed number of 
revolutions. 


Diagram 94 illustrates a generator with a mechanical 
governor. The regulation of the maximum output is 
affected by the centrifugal governor at C and C, which 
keeps the speed of the machine constant. The variations 
in speed are taken care of by the automatic clutch. The 
clutch, A and B, will slip more or less according to the 
speed of the engine, and the amount of such slippage is 
controlled by the governor, C C. As soon as the speed of 
the armature increases beyond 'the rated number of revo¬ 
lutions, the governor at C C will act on the friction clutch 
at A and B; in other words, the two clutch halves, A and 
B, will be pulled apart and slip in sueh a manner that the 
armature will rotate not faster than the predetermined 
speed. 

The Graphite Disc Regulation of Constant Voltage.— 
The regulation of constant voltage is maintained by pres¬ 
sure upon the graphite disc as shown at diagram 95, which 
are pressed together by the lever K, by pressure of coil 
spring J; the less the pressure the greater the resistance 
thrown into the field winding; for if the discs are not 
close and tight, resistance is offered to flow of current; 
note the pressure upon these discs is also controlled by the 
electro magnet. The stronger the current flow from the 
generator, the greater will be the magnetic pull on K, and 
J; thereby taking pressure off the graphite disc they separ¬ 
ate offering a resistance which cuts down the current 
going around the field cores, thus cutting down the mag¬ 
netic field produced in the generator and therefore causing 
the current output from the generator to be constant at all 
speeds. 

The Thermal Principle of Control.—At diagram 96, the action is to reduce the 
strength of the field magnets at high speed by means of a counter excitation produced 
by a few turns of magnetic wire called a bucking coil on the field pole, figure 2, diagram 
96. The amount of current passing through the bucking coil is determined automatically 
by the varying resistance of a small core of iron wire called the ballast coil, figure 3, 
diagram 96, which is made in the form of a cartridge fuse, and is carried in clips on the 
switchboard in the main lie between the dynamo and the battery. At low dynamo 
speed and output of current, this ballast coil is cold and acts as a short circuit to divert 
the current from the field bucking coil. As the output increases, the iron wire becomes 
heated, although its resistance remains practically the same as when cold, until reaching 
a certain critical temperature just below the dull red heat. Its resistance goes up with a 
jump so that practically speaking it will not permit another ampere to pass and after 
that the excess current must pass through the field bucking coil. At car speed below 
fifteen miles an hour the dynamo acts as a simple, uncontrolled, shunt-wound machine, 
while at the higher speeds, owing to the counter-effect of the bucking coil, the resultant 
excitation is barely one sixth of the excitation due to the main shunt field coil alone. In 
order to keep the current in the main shunt field coil as nearly constant as possible, it is 
connected at a point below the ballast coil, figure 2, instead of directly across the brashes; 



Regulator 































































modern electrical motor car equipment 


67 


f-QWlAffl— 

IKON BAlLAST 


AUTOMATIC 

CUT-OUT_ 



WVW\r~ 

BUCKING COIL 

n/VWWV 


if. 


BATTERY 


MAIN riELt) COIL 


Q 0 

omp; 


Dia% » j 6 -Diagram 0 f Rushmore generating sys¬ 
tem. The bucking coil is a “series” winding 
on the field The main field winding is “shunt¬ 
ed’ ’ across. Out-out is the usual magnetic type. 


(RON 

BALLAST 

COIL 



Fig. 2. — Diagram 
showing the main 
field winding and 
bucking coil series 
winding and location 
of “ballast coil’’ in 
circuit. 



Fig 3.—The ‘Iron 

wire” ‘thermal’ type 
regulator of current, 

jailed ‘ballast coil” 
which allows a certain 
quantity of current to 
pass, but beyond that 
quantity the iron wire 
heats and offers resist¬ 
ance to flow of current 
in field, therefore the 
current must go through 
the bucking coil or series 
winding (in figs. 1 & 2) 
which action does not 
permit the current to in¬ 
crease but keeps it at a, 
constant strength. 


thus it does not feel the fluctuation of voltage at the brushes. The ballast coil which 
allows a certain quantity of current to pass, but beyond that quantity the iron wire 
heats and offers resistance to the flow of current in the field; therefore the current must 
go through the bucking coils or series winding in figures 1 and 2, which action does not 
permit the current to increase, but keeps it at a constant strairt. 

Third Brush Regulation.—In diagram 97 the 
regulation of the generator is affected by what 
is known as a third brush excitation. From 
the foregoing explanations of the generating of 
electricity, and from the fact that the voltage 
generated varies directly with the speed, it is 
evident in order to maintain a nearly constant 
voltage with a variable speed it becomes neces¬ 
sary to decrease the magnetic field, as the speed 
increases. Since the magnetic field of the generator 
is produced by the current in the shunt field wind¬ 
ings, it is evident that should the shunt field current 
decrease, as the speed of the engine increases, the 
regulation would be affected. In order to fully under¬ 
stand this explanation it must be borne in mind that 
a current of electricity always has a magnetic effect, 
whether this is desirable or not. Referring to dia¬ 
gram 97, the theory of this regulation is as follows; 
the full voltage of the generator is obtained from the 
large brushes, marked C and D. When the magnetic 
field from the pole pieces, N and S, is not disturbed 
by any other influence, each coil is generating uni¬ 
formly as it passes under the pole pieces. The voltage from the commutator bar to 
the next one gradually increases from zero to full voltage, depending on position of 
coils to which the commutator bar is attached. The voltage from the brash, C, is about 
five volts when the total voltage from the brash C to brash D is six and one half volts, 
and five volts is applied to the shunt field winder. This five volts is sufficient to cause 
approximately 1% amperes to flow in the shunt field winding. As the speed of the 
generator is increased the voltage is increased, causing the current to charge the storage 
battery and supply the lights. 

The charging current flows through the armature windings producing a magnetic 
effect in the direction of the arrow B. This magnetic effect acts upon the main magnetic 


SA'evST W/AfOfA/G Vk'/cw 

/7*GA'£-77C 



The third 
brush regu¬ 
lation 

























































MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


field, which is in the direction of the arrow, A, with the result that the magnetic field is 
twisted out of its original position in very much the same manner as two streams of 
water coming together are each deflected from their original position. This deflection 
•©.uses the magnetic field to be strong at the pole tips, marked G and F, and weak at th« 
opposite pole tips, with the result that the coil generates a very low voltage while 
passing from the brush E to the brush D; the coils at this time are under the pole tips 
having a weak field and generate a greater part of their voltage while passing from the 
brush, C, to E. The amount of this variation depends upon the speed that the generator 
is driven, with the result that the shunt field current decreases as the speed increase®. 
The third brush, E, is adjustable. Moving this brush in direction of rotation increases 
the charging rate to battery; moving brush in opposite direction decreases the charging 
rate. 

CHAPTER 33. THE ELECTRIC MOTOR. 

In construction the electric motor differs in no essential respect from the dynamo. 
Diagram 98 illustrates the principle of the electric motor. A current from an outside 
source flows from A through the conductor in one direction on one side, and in the 



Biag. #. 98 Show & simple; 

Electrical Motor 

opposite direction on the other side. Remember that when a current flows over a wire 
from you there are always circular fields of magnetism flowing clockwise around the 
wire. Now the motor rule is stated thus: A current in a magnetic field tends to move 
away from the side on .which its lines are added to those of the field; therefore, the con¬ 
ductor on the top is urged downward by the influence of the field, and the conductor in 
the bottom is urged upward. The armature will therefore begin to rotate, and this 
rotation will continue as long as the current is sent in at A and comes out at B. To 
reverse the motion all that is necessary is to arrange the current to flow in at B and 
out at A, while the magnetic field remains unchanged. 

The Application of the Electric Starting Motor to the Engine.—The starting motor 
can drive the gasoline engine through the fly wheel or by connection with the crank 
shaft, or drive through the transmission shaft. The drive through the fly wheel is the 
most popular. 

Mechanical Gear Shift.—The action of the starting switch with the mechanical gear 
shift in diagram 99 illustrates very clearly its principle. The contact making parts 
of the switch are shown mounted directly on the gear shift drive, though it can be 
mounted on any rod interconnected with the gear shift rod. At A is shown the off- 
position of the short pinion and switch contractor. Pressure on the starting lever 
moves the shift rod, first to the position B, closing the motor circuit at P and P, through 













MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


ee 


the resistance R; this starts the motor at a low speed. Further motion on the shift rod t» 
position C opens the electric circuit. The motor and pinion continue to turn, owing to 



Diag. f 99 Show 
Shift. 


BAT. STARTING 



their momentum. When position C is reached the pinion is still turning slow, so that 
it cannot fail to mesh with the gear; but, as the power is turned off the motor, there is 
no difficulty in sliding the teeth into full engagement. As soon as the teeth do engage 
the pressure on the starting lever shifts the rod to position D, closing the electric 
circuit at Q. After the pinion and gear has meshed a sufficient distance to present a 
good bearing length on the teeth, this connects the motor directly on the storage battery 
so that full power is developed, and it turns the engine over until the starting lever is 
released. When the pressure is removed from the starting lever, a spring returns ths 
shift rod and all parts to position A. This releases the gears and opens the electric 
circuit and the motor comes to rest. 

The Bendix Automatic Gear Shifting Pinion.—This type is used on a majority of 
ears to-day. The gear ratio is 10 V 2 to 1, or a 12-tooth pinion to a 126-tooth gear on the fly 
wheel. The starting motor will crank the engine at a speed of 150 to 200 revolutions 
per minute. This automatic drive is shown at Diagram 100. 



Diag. f 100 The Bendix Auto¬ 
matic Gear Shifting Pinion 


No arrangement or levers to slide the pinion into mesh, nor any overrunning clutches 
are required. It is only necessary to operate the switch of the motor, or press a switch 
button, and this can be done at the wrong time, when the engine is already running, 












































70 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


without damage. The parts are few and simple. The armature shaft has a screwed 
extension with an outer bearing, B, and carries the pinion, P. The weight is solidly 
attached to the pinion and the latter is loose enough on the shaft to always occupy the 
position shown at diagram 100., With the weight underneath when the shaft is idle, the 
leading screw is triple thread. On starting the motor the inertia of the weight, W, 
causes it and the pinion to be carried quickly along the shaft into mesh with the teeth 
on the fly wheel, where it remains performing the operation of cranking until the 
engine commences to fire. When the direction of the drive is reversed coming from the 
wheel to the pinion throws out the pinion. The spring, S, is simply to ease the shock 
of starting by permitting a side play between the motor shaft and the screwed extension. 
The teeth on both fly wheel and pinion are beveled on the entering side for easy engage¬ 
ments. 

The Electrical Automatic Gear Shift.—Diagram 101 illustrates the construction of 
the motor. The armature can be shifted endwise in its bearings parallel to its axis. In 
the normal or nonoperating position, the armature is held out of its electrical center, 
or in other words, out of line with the pole shoes by means of a spiral spring, as shown 
in figure 2, diagram 101 at the bottom, in the commutator end of the armature shaft; 
therefore, when in the normal position the pinion on drive shaft of the starting motor 



/'W-- FIELD WIHDINQ. B- BRUSHES, 

O- STARTING PEDAL. E- RESISTANCE. 


B ta n r/.y<r s-n/rcs* 


AWT 


SPRING 


Diag. 101 The Electrical Automatic Gear Shift 























































































































































MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


n 

is out of mesh with the gear on the fly wheel of the engine. The motor is regularly pro¬ 
vided with three terminals (W,Wl,andW2) two of which are heavy, or of larger diameter 
than the others. The two heavier terminals are for the main circuit and the single smaH 
terminal is for the shunt circuit. 

Principle of Operation.—During the first part of the downward movement of the 
switch pedal, D, an electric ctirrent is established which causes the current ffom the 
storage battery to pass through the switch shunt, E. The amount of current that can 
flow is limited by the resistance E of the circuit, but of the current which passes through 
the switch shunt a small portion is allowed to flow through the motor armature, while the 
greater portion flows through the motor field coils, forming there a strong electromag¬ 
net. The result is a powerful attraction between the field coils and the armature, causing 
the armature to be drawn endwise into the magnetic center of the motor, or in other 
words, into its working position between the pole shoes. The passing of the small 
current through the armature causes the armature to rotate slowly, and as the rotary 
motion occurs simultaneously with the shifting of the armature endwise, the meshing of 
the motor pinion P with the gear ring on the engine fly wheel F G in figure 2 is ac¬ 
complished quickly and positively. As the switch pedal, D, reaches its limits of motion 
at C, the flow of battery current through the switch shunt as well as that through the 
shunt cables to the field coil is interrupted and a straight series motor in connection is 
established, allowing the entire current to pass through the motor fields and armature 
windings and causing the engine to turn over until it starts firing. As soon as the 
engine starts the starting motor is relieved of its load, and the current passing through 
it drops rapidly in volume; this being a characteristic of series motors. In consequence 
the strength of the field magnets is lessened to a point where the spiral spring in the 
end of the armature shaft figure 2 overcomes the magnetic attraction, holding the 
armature and returns it to the original or nonoperating position. It is this action that 
automatically and positively throws the armature shaft pinion out of mesh with the 
fly wheel ring gear. Thereafter until the starting switch is released and current which 
continues to pass through the armature will merely cause the latter to revolve freely, 
but without meshing with the fly wheel, due to the fact that the amount of current 
utilized when the motor is running free is not sufficient to overcome the tension of the 
spiral spring. 


CHAPTER 34. FUSES. 

Fuses are very important, particularly when the ground or single wire system is 
used. They melt and open the circuit and prevent discharge of battery. There are three 
types of fuses shown in diagram 102. First, the cartridge type, figure 3; the visible 
type, figure 4, and the open type, figure 2. The visible type will instantly show when 
burnt out, whereas in the cartridge type a hole will be blown in the side of the shell. 
The cartridge and invisible type can be slipped into place by hand: the open type requires 
a screwdriver. The visible type, shown in figure 4, is a type in general use. The 
capacity of the fuse in each circuit should be as follows: sidelights, 3 to 5 amperes; head¬ 
lights, 15 amperes; extra circuits, when provided, 15 amperes. The extra circuits may 
be used for dome or pillar lights, horn, etc., as desired. In other words, the size of the 
fuse is determined by the amount of current that is to pass through it. If the fuse is to 
be placed in the headlight and taillight circuit, and this circuit uses 5% amperes, a 15 
ampere fuse is ample protection. 



72 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


Multiple Switch Connections for Lighting Circuits.—Example of a multiple switch 
is shown in diagram 103. To give the reader an idea of the various kinds of connections 
which may be made by one switch, the contacts have been numbered 1, 2, 3, 4. Note the 



FIG.3 FIG A- FUSt 




Diag.l02There are three types of fuses, the car¬ 
tridge type (3) the visible type (4) and 
the open type (2) 


illustration of 103; if 1 and 4 connect, side and taillights are on; if 1 and 2 and 3 
connect, then side, tail, and headlights are on; a study of the illustration will make the 
diagram clear. The switch for turning the lights off and on is usually placed on the dash 
and should be of the push button type. Instead of using one switch it is advisable to 
have several push button switches in one bank so that the headlights, sidelights, and 
taillights will be independent; for instance, it is not always necessary to have the lights 



Diagram 103. Multiple switch connections for lighting circuits. 

burning when running through well lighted districts; therefore they can be switched 
off and current saved. In many instances the taillights and dashlights are connected 
in series; if the taillights should happen to go out, the dashlight will also. 









































































MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


7S 



Diag. 104 Th@ Delco single Unit System with Motor 
Generator and Ignition System combined 































































































74 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 

The Deko Electric Motor Generator and Ignition Unit.—In this system we have t'h* 
motor, generator, ignition coil, distributor, and timer, all compact into one unit whic'h 
has proven to be very efficient. 

The Starting Operation.—Diagram 104 shows the operation of the generator and 
the motor brush switches, both of which are operated by the pole rod, E; this also oper¬ 
ates the starting gear; the complete starting operation is as follows: when either the 
M or B in diagram 3 buttons on the combination switch is pulled out the circuit between 
the generator and the storage battery is closed, the current will flow from the storage 
battery through the generator windings, which cause it to rotate slowly. As the starting 
pedal is pushed out it operates the pole rod, E, which causes the gear, J, in figure 1 of 
the motor clutch to mesh with the motor pinion, and this causes the motor clutch to rotate 
slowly. As the pedal is pushed further out, the gear, G, meshes with the teeth on the 
face of the fly wheel. As soon as the gears are meshed on the fly wheel the pull rod, 
E, raises the lower generator brushes of the commutator, as shown in figure 2. When 
the pull rod, E, has been moved forward enough by the starting pedal to bring the gears 
fully in mesh, it then allows the motor brushes to drop on the commutator, and completes 
the cranking circuit. After the engine is started, the pull rod, E, throws gear, G, out of 
mesh with fly wheel, raises motor brushes, and places the generator brushes on its 
commutator. 

The Generator Clutch.—A clicking sound will be heard during the motoring of the 
generator. This is caused by the overrunning of the clutch in the forward end of the 
generator. The purpose of the generator clutch fs to allow the armature to revolve 
at a higher speed than the pump shaft during the cranking operation and permitting 
the pump shaft to drive the armature when the engine is running on its own power. 
Spiral teeth are cut on the outer face of this clutch for driving the distributor. This 
portion of the clutch is connected by an Oldham Coupling to the pump shaft; therefore, 
its relation to the pump shaft is always the same and does not throw the ignition out of 
time during the cranking operation. 

CHAPTER 35. COMMUTATOR TROUBLES. 

The troubles which commutators are subject to, either on motors or generators, are, 
arcing at the brushes, weak brush holder springs, loose pig tails or connections of the 
wires to the brushes, sticking brushes, overloading of the generator, and short circuits 
between the motor and generator windings. 

Mica Protruding Cause of Trouble.— 

Diagram 105 illustrates the armature, 
showing the brushes and commutator. At 
A, figure 105, is shown a commutator with 
the mica insulation between the segments 
protruding above the commutator segments; 
the cause of this mica protruding is the fact 
that the copper segments are softer than the 
mica, and naturally wear faster until the 
mica is so far above the segments the 
brushes cannot make good contact; therefore 
arcing occurs and burns and blackens the 
commutator. Most of the troubles of this 
nature are due to the use of carbon brushes 
which are not hard enough to wear the 
mica down. The commutator, however, 
where metal brushes are used, the troubles 
are not so great as they are harder. 

To Remedy the Trouble of the Protruding Mica is to cut the mica down between the 






MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


75 


segments, say a little over one sixty-fourth of an inch deep between segments. When 
mica is properly cut, it will have the appearance as per lower illustration at B, 105. 

Commutator Noises.—If commutator makes a noise and the trouble is not from the 
protruding mica the commutator can be cleaned or new brushes fitted, and if necessary 
smoothed down with sandpaper; use 00 smooth sandpaper; never use emery cloth. 
To clean the commutator use a piece of cloth dampened with gasoline so as to remove 
grease and dirt. Never use waste. 

Fitting Brushes.—Brushes must always make a good contact with the commutator. 
They should have sufficient spring tension to press the brushes to the commutator, yet 
move freely. When fitting new generator brushes, or motor brushes, they do not 
always fit commutator perfectly; that is, they are not rounded to the commutator sur¬ 
face. This can be remedied by placing the rough side of a strip of sandpaper under the 
brush. When it is in its brush holder, work the strip back and forth, holding the ends 
close together. The entire surface of the brush must be treated, otherwise it will be 
uneven. The pig tails or brush connections must also be kept tightened. 

CHAPTER 36. ARMATURE TROUBLES. 

Armature windings may be burned out or grounded. When burnt out the trouble 
may be due to a current overload, or due to improper regulation, a soaked winding, or a 
steady or prolonged flow from the battery due to failure of circuit breaker con¬ 
tact points to open; a grounded armature winding is due to defective insulation. 

CHAPTER 37. LOCATING ARMATURE TROUBLES. 

Armature troubles are sometimes found in the attaching leads at the commutator 
segments. The soldered attachment may be thrown off in revolving. This can be 
soldered back to the segments by an electrician. Dim lamps, low voltage, the under¬ 
charging battery might be the results of armature trouble. One of the armature coils 
might be short-circuited or burnt out, or a connection might be loose or broken. Any 
defect in the armature will be indicated by an uneven torque. In the case of the 
generator, this may be very easily tested by disconnecting the driving mechanism, hold¬ 
ing the cut out points closed, and allowing the generator to operate as a motor. If 
everything is all right, the armature will rotate evenly, and in the same direction as 
when it operates as a generator. Whether the torque is even or not, may be de¬ 
termined by holding the end of the armature shaft in the hand and noting whether 
the pull is steady; an uneven pull means that one or more of the coils is not working. 
It is just like an engine with a missing cylinder. If an armature coil is burned out or 
there is a broken connection, the armature will invariably stop at a certain point. If this 
is the case, the commutator segments between the two ends of the coil will also be 
burned. Sometimes a broken connection occurs at the junction between commutator 
bar and the coil, in which case the remedy is to resolder. 

CHAPTER 38. FIELD WINDING TROUBLES. 

A grounded generator or dynamo can be caused by an accumulation of dust worn 
from the brushes or a defective insulation of the armature or field coil. The field 
coil may become grounded due to a watersoaked generator or short circuited through 
burning out, by running the generator with the battery disconnected. You should not, 
for any reason, run a car if the battery is disconnected from the circuit, unless you have 
disconnected the chain driving the generator, or the generator itself has been removed; 
or place dry cells in the place of the storage battery to take the storage battery place. 
The generator must be kept free from excessive moisture. Ordinary moisture will not 
affect it, but should not be allowed to become thoroughly wet, such as would be the 
case if the generator or motor were to become submerged under water. This is likely 





MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


76 

to happen while fording a stream. If the generator is wet, it should not be operated 
until it is thoroughly dried out. This can be done by removing from the car and baking 
twenty-four hours in an oven whose temperature shall not exceed 220 degrees Fahren¬ 
heit. A higher temperature in the baking oven would damage the insulation. 

CHAPTER 39. STORAGE BATTERY POINTERS. 

1st; Learn to prepare the electrotype. Use a large earthen crock or lead vessel with 
burnt seams. One part of chemical pure concentrated sulphuric acid is mixed with 
several parts of water. The proportion of water varying with the type of cell. Always 
pour the acid into the water, never the reverse. Use pure water, either distilled or rain 
water. Allow the electrolight to cool before placing in the cell. The specific gravity 
should be thirteen hundred. Add distilled water if a higher reading is obtained. 

Plate should always be at least one half inch below surface of solution. 

2d; Woolen cloth is little affected by acid. 

3d; Ammonia immediately applied to a splash of acid on the clothes neutralizes the 
acid and prevents a hole being burned in the material. 

4th; In case a bit of acid splashes into the eye, wash well with warm water and put 
into the eye a drop of olive oil. 

5th; Avoid the use of an open flame in a room where a storage battery is being 
charged, or in which it has been left for some time, as an xplosive mixture of air and 
hydrogen may be formed. 

6th; Storage batteries are rated in ampere hour, this being based on the steady 
current the battery will discharge. A battery that will discharge at five amperes for 
eight hours without the voltage falling below 1.75 is rated at a 40-ampere hour battery. 
This does not mean that 40 amperes would be the output of the battery if discharged 
in one hour. The ampere hour capacity decreases with the increase in current output. 

7th; The current in charging should be kept within the maker’s specified limits. 
One authority advises for rapid charging, covering a period of three hours, fifty per 
cent, thirty-three per cent, 16 2-3 per cent of the total for each consecutive hour. 

8th; The E M F of the charging current at starting the charge should be about 5 
per cent higher than the normal E M F of the battery. After a few minutes this voltage 
may be ten or fifteen per cent higher than the normal battery E M F. However, the 
battery is kept in the best condition by using a constant charging current, and if 
necessary to maintain this, the voltage may be raised to 25 per cent higher than the 
normal battery voltage. 

9th; Be sure the positive pole of the charging mains is connected to the positive 
side of the battery. 

' 10th; To determine the polarity hold the two wires in a glass of acidulated water or 
electrolight, keeping them at least one half inch apart. Gas bubbles will collect at the 
negative lead. 

11th; A cell is fully charged if with a constant current the voltage and specific 
gravity do not change in one hour, when the plates decidedly increase the quantity of 
gas given off. When the specific gravity measures 1300 and the voltage from 2 5-10ths 
to 2 7-10ths. When the negative plate assumes a light gray color, and the positive 
plate turns a dark brown. 

12th; Never adopt the method of putting a wire across the positive and negative 
terminals to see if there is any spark. It is almost a dead short circuit, and if the cell be 
of small capacity of say 30 ampere hour, and the wire number 16 copper, the current 
may be anything from 30 to 100 amperes for a fraction of time which 1 , when calculated 
is a very appreciable amount of the total capacity. If only for a second of time duration 
it is also very detrimental to the cell, assisting the deterioration of the plates or active 
material thereon. 

13th: Lead cells should not be discharged below 1 7-10th volts. 



MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


T7 


14th; Excessive boiling will loosen the active material on the plates. 

15th; If the cells are hot, while charging, reduce the charging current. 

16th; If a battery is not in use, give it a short charge once a month. 

17th; If white sulphate is formed on the plates, it may be reduced by charging at 
& high rate for a few hours, and overcharging at a low rate for two or three days. 

18th; Continued sulphating will buckle the plates, as will also too rapid discharging. 

19th; A cell that has been short circuited should be disconnected from' the battery 
and charged and discharged several times separately. 

20th; Caring for the battery when not in use; One way to do this is to charge the 
battery fully, then siphon the electrolight out of the jars to be kept until used again. 
The plates must then be removed and stored. 

21st; Never allow the cells to stand in a discharged condition, as it becomes very 
difficult to get them properly charged if left standing any length of time, unless great 
care is taken during the succeeding charge. 

22d; If terminals begin to corrode, clean them off thoroughly and grease them with 
vaseline. 

23d; Voltage reading should be taken only when charging or discharging. 

24th; The temperature of the battery should never exceed 100 degrees Fahrenheit. 

25th; Use only distilled water to replace loss from evaporation. Add acid only in 
case electrolight should be splashed out. 

26th: Each time you charge battery bring the gravity up to maximum or charge 
until it has remained constant for at least one hour in every cell. 

27th; When charging the battery put in at least 20 per cent more current (ampere 
hour) than is taken out, and at every third charge give it a 50 per cent overcharge at 
the finished rate for the general good of the battery. 

28th; Voltage readings are only approximate; gravity readings give correct indica¬ 
tions. 

29th; Keep the box containing the battery perfectly dry; if any acid is spilled 
into the box wipe it off carefully with a piece of waste dipped in ammonia water. 

30th; When charging at the finished rate, or 24 hour rate, leave the battery on until 
bubbles begin to rise in the electrolight, then for at least one hour longer. 

31st; Never add acid or electrolight to the cell except to replace losses from spilling. 

32d; In cases where the specific gravity will not show any rise during or at the end 
of its charging, it indicates a short circuit and the cell has not received its charge. 

33d; In cases where the specific gravity comes up to 1300 at the end of its charge, 
but falls to a lower figure during a period of idleness, or stands for say twenty-four 
hours or forty-eight hours, this also indicates a short circuit or else local action or 
... . discharge due to contamination of the electrolight by‘some impurity. 

34th; The charge must always be given from a direct current circuit, never an 
alternating unless a rectifier is used, and great care taken to connect the positive wire 
to the positive terminal of the battery, either directly or through the resistance which is 
usually necessary. If connected in a reverse direction, very serious injury to battery will 
result. 

CHAPTER 40. SUMMARY OF STARTING TROUBLE. 

Starting Motor Cranks the Engine Very Slowly.—Battery almost discharged. Bat¬ 
tery sulphated; engine stiff; brushes loose; and poor contact. 

Starting Motor Does Not Rotate at All.—Battery may be discharged; starting 
■witch not making good contact; motor brushes may not make contact with commutator; 
battery terminals may not make good contact. 

Starting Motor Rotates But Does Not Crank Engine.—Roller clutch does not work 
properly; gears not properly meshed; if Benedict’s automatic spring broken. 

Starting Motor Cranks Engine A Few Revolutions and Then Stops.—Battery weak; 
almost discharged; loose switch contact; engine stiff. 




78 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


Starting Motor Cranks Engine but Will Not Pick Up Under Its Own Power.—These 
symptoms indicate that trouble is not in the starting system, if Benedict’s starter gear 
on thread shaft may be stuck or spring broken. 

A Weak Starting Motor is Sometimes Caused by using carbon brushes instead of 
metallic composition brushes. The metallic composition brushes have three or four 
times the conductivity that carbon brushes have, and for this reason their replacement by 
cheap carbon will not allow a sufficient current to pass. 

If the Battery is All Right, Proceed to Examine the Connection, beginning with the 
battery. The current may be shortened, due to electrolight spilled on the top of it; or 
terminals may be sulphate, in which case enough resistance will be offered to the 
current to prevent the motor operating properly. Scrape off the sulphate, and wash all 
the surrounding metal parts in carbonate of soda, or some other convenient alkali, then 
replace the wire and coat them thoroughly with vaseline to prevent further corrosion: 
With the starting switch closed beginning with one of the wires running from the 
battery loosing the various connections in the starting circuit by one, and noting at 
each point whether there is current flowing by pulling the wire away from the terminal. 
If there is no current, the motor will not operate at all, and either there is a dead short 
circuit in some part of the system, or there is a broken wire or connection. The 
inspection should show where the trouble is. 

The Battery Terminals Were Grounded to the Frame.—On single wire systems 
should be examined to see if connection is O. K. This terminal and its contact surface 
t should be kept celan and drawn very tight if not soldered. 

CHAPTER 41. CUT OUT RELAY TROUBLES AND REMEDIES. 

The proper care of a modern car’s electric lighting and starting system, though 
apparently a matter of some difficulty, is in reality quite simple, providing a few general 
instructions are thoroughly memorized. In all cut out relays or controllers found in 
battery or dynamo wiring, contact points should be kept perfectly clean in order to 
insure their reliable action. Be sure that the contact points of the cut out actually make 
contact. The cut out armature may be drawn to the magnetic core, bu points may not 
come really together. Failure of the cut out to operate may be due to several things. 

In the first place, a back kick or back firing of the engine will cause the points to 
close and stay closed, and whenever this happens no time should be lost in separating 
the points. 

This , may be done by starting the engine again or by pulling them apart with the 
hands. 

There are several mechanical reasons why the cut out may fail to operate. The 
points may be too near together or too far apart. The points may be rough or pitted. 
The points should be smoothed with a fine file and then adjusted. The spring which 
holds the cut out open may be weak or broken, or the armature may stick, due to 
worn or tight parts or dirt. 

Electrical Defects.—In the operation of the cut out are confined to bad connections 
or grounds. These troubles are rare and should be quickly evident after an inspection. 
Failure of the cut out armature to open when the engine is stopped would indicate 
trouble in the series coil, while failure to close might be caused by a defect in either 
series or shunt coil. To determine whether the cut out is working properly, the car should 
be driven on high gear at speed varying from six to fifteen miles per hour, and the 
speed at which the cut out operates should be noted. The correct speed can usually be 
found from the maker’s instruction book. 

Circuits.—See. that all circuits between dynamo and battery are intact, and all 
binding posts and contacts tight. 





79 


_ MODERN electrical motor car equipment 

TROUBLE INDICATIONS AS TOLD BY THE AMMETER. 

Ammeter troubles may be divided into two classes; those that manifest themselves 
when the engine is idle, and those that only show themselves when the engine is running. 

Remember that the ammeter should show charge at speeds above eight or ten miles 
per hour, and that when the engine is at rest and lights turned off, the needle should 
stand at zero, and not show discharge. It shows discharge when lights are on, and engine 
idle, or speed less than eight miles per hour; in other words, the battery is then dis¬ 
charging. 

If ammeter shows charge instead of discharge, and shows discharge instead of 
charge, it indicates that the wires connected to the rear of armature should be reversed. 

If ammeter indicates zero and the dynamo should be charging battery, it shows that 
the circuit is open or the dynamo is at fault. 

Ammeter does not indicate charge when engine speeds up, but indicates discharge 
when lights are turned on and engine at rest, dynamo or regulator not working properly. 
Dynamo brushes do not slide freely in holders. 

Ammeter does not indicate charge, engine speds up and does not indicate discharge 
when lights are turned on and engine at rest, open or loose connections in the battery 
circuit, battery terminals loose, dynamo terminals loose, ammeter may be at fault, am¬ 
meter indicates discharge, lights turned off and engine at rest, ammeter pointer bent, 
insulation on wires injured, permitting contact with frame causing short circuit. If, 
however, it I’eads discharge, either there is a ground or the ammeter hand is stuck, 
bent, or out of calibration: that is, it gives an incorrect amperage indication. If the 
trouble seems to be in the ammeter, it is well to place a test ammeter in the circuit to 
check the first instrument. If the instrument registers incorrectly, it should be returned 
to the maker for repair. 

Ammeter indicates charge when engine is at rest, ammeter pointer bent, battery 
connections wrong, but current is flowing. 

Ammeter charge indications below normal, dynamo output varies with condition of 
battery. 

Ammeter discharges indications above normal, lamp load excessive, lamp wires in 
contact with frame. 

Ammeter pointer jerks intermittently to discharge. Limits of scale while engine is 
speeding up, short circuit in system. Fuse blows out repeatedly, lamp wires in contact 
with frame, lamps defective, short circuited; try new bulb. 

Ammeter or indicator registers discharge with all lights off and engine idle, short 
circuit in wiring from battery to switch, or battery at junction block, ammeter out of 
adjustment. 

If larger than standard bulbs or extra lamps are used, when turned on, discharge 
indications will be higher; this will cause charge indications to be lower. When car is 
running at twelve mile per hour or over, the ammeter may even indicate discharge. 
This is not serious unless there is insufficient day driving or excessive use of lamps at 
night, thereby permitting battery to discharge. 

Ammeter exposes short circuit. If the engine back fires when being shut down and 
makes one or more revolutions in the reverse direction, the ammeter needle may be 
found pointing to the extreme left hand side of the scale. This is caused by the 
circuit breaker contact being half closed by means of a dead short circuit of the battery 
through the generator. This must be corrected at once by starting the engine. 

The ammeter will always indicate if short circuits exist in any part of the wiring 
except on the battery to the switch buzz bar and in the starting motor circuit. 





80 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


CHAPTER 42. SHORT CIRCUITS. 

The largest number of electric lighting and starting and ignition troubles is caused 
from short circuits; therefore, it will be well for the reader to familiarize himself with 
the meaning of the terms used in connection therewith, viz, short circuits, open circuits, 
and ground circuits. 

Short circuits mean that two wires are in metallic connection when they ought not 
to be. Under such condition the battery will be partially or completely discharged and 
no lights, or dim lights will be the result. A short circuit may occur at any part in the 
wiring system, but is usually found at the points of connections or switch terminals and 
is caused by frayed ends of wires bridging across terminals or short circuits by abrasion, 
heat of the engine, oil, dampness, or defective insulation. A short circuit may be 
caused by a wire being in contact with the frame. This is also called a ground. 

Bad or Dead Short Circuits.—In this case a cable or wire has probably been cut or 
jammed, or burned so that the insulation has been destroyed and a good firm contact 
is made with the frame, results—the lights will suddenly appear and go out, but in 
reality they glow very faintly. A short circuit of this kind will very soon discharge the 
battery. 

Slight Short Circuit.—In this case a short circuited connection is of such high 
resistance that only a small amount of electricity is lost. Such a circuit is often 
known as a leak. Results the battery will not hold the charge, and in some cases may 
become entirely discharged over night. This kind of a short circuit is first noticed when 
the starter seems weak and the light seems to grow dim at low car speed, and brighten 
up as the dynamo cuts in. 

Indications of a Short Circuit.—First, battery will become exhausted regardless of 
the charging it receives. Second; battery will discharge over night. Third; lamps 
when turned on, will burn dimly. Fourth, ammeter pointer may go to the limit 
of discharge scale. Fifth; starting motor may act sluggish or not at all. Sixth; fuses 
blow out repeatedly. 

A short circuit in any lamp circuit will usually cause a fuse to blow or melt. If 
this occurs, it is evident that the wires leading from the fuse are in contact with the 
ground or frame of car, or other metals, or that insulation has been injured and con¬ 
ductor is in contact with other metals, thereby grounding it to frame. The wire must 
be inspected along its entire length until trouble has been located and corrected. Wires 
having injured insulation should be wrapped with friction tape to prevent contact with 
frame or other conductive materials. 

Some Causes for Short Circuits: First of all, the ground may be in the battery 
itself, and may be caused by buckled plates, or an accumulation of sediment. The 
former trouble is usually the result of charging or discharging the battery at too high 
a rate which causes the plates to bow, and this creates an excessive pressure on the 
wood separators between the plates. The vibration of the car soon causes one plate to 
wear through the separator and come in contact with its neighbor, thus causing an 
internal short, and the latter is due to neglect to clean the sediment out of the chamber 
provided for its collections become filled. This would be termed an internal short circuit. 

The next place to look for a short circuit is on the top of battery. Spilled acid may 
cause a partial short circuit. The top of the battery should be wiped clean, treated with a 
solution of potash, and then the metal parts should be treated with vaseline. If the 
current is flowing through the external circuit, this fact may be determined by dis¬ 
connecting one of the battery wires and then touching it for an instant to the terminal 
it was just removed from. If any current is flowing a spark w-11 bo seer. If any con¬ 
siderable amount of electrical energy is being lost, this fact should also be indicated on 
the ammeter if one is fitted. 



MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


81 


As a precaution the starting switch should be examined, as it is possible that it 
did not release fully the last time it was used, and that some current is short circuiting 
through it. „ 

Having gone through these preliminaries, the next step is to start from the battery 
and examine all the circuits, taking the main one first. Disconnect the main feed wires 
where they enter the junction box, and note whether the ammeter gos back to zero; if 
it does, there is a ground between this point and the battery. 

Put these wires back on, and then disconnect all other wires from the junction box. 
If current is still flowing the trouble is in the junction box, but if junction box is found 
O. K., it must be in one of the circuits running from this point. If this is so, then 
remove wires and test each separately. 

Testing for Short Circuit.—First, be sure that a short circuit exists. This test can 
be made several ways. The ammeter on dash will indicate trouble, but if there is no 
ammeter on the car, then open all switches, disconnect one terminal of the battery, and 
strike the connection lightly against the battery terminal in quick succession. If a 
spark occurs, even though very slight, it indicates a ground or a short circuit, then 
all is left is to proceed and find the short circuit. 

CHAPTER 43. A DIGEST OF LAMP TROUBLE. 

Lamps Do Not Light Up.—Examine fuse block or blown fuse. If the fuse is blown, 
do not replace it immediately, but look over the wiring for an accidental ground, or short 
circuit. If the fuse in the headlight circuit blows, turn off the headlight switch until the 
trouble is located and removed. In looking for grounds, abrasion of the insulation on 
the wiie or metallic contact between the wires or between currents carrying parts of 
the wire devices, and the metal of the car should be looked for. When the trouble has 
been located and corrected, then replace the blown fuse with others of the same capacity. 
If fuse is found not blown, look for open circuit, loose contact, battery disconnected or 
accidently run down, or burnt out lamps. Examine the cut out switch of the generator 
to see that it is properly disconnecting the generator circuit. This switch should be in an 
open position, when the engine is not running and should be in a closed position when 
the generator is running at any speed over 300 to 450 revolutions per minute. 

Lamps in One Circuit Do Not Burn.—This may be caused by the lamps being burnt 
out. Try another lamp in the same socket. If fuse is found blown, try the same fuse in 
another circuit. If the fuse is blown do not replace it immediately but look over the wire 
for accidental ground or short circuit. If the trouble cannot be located immediately, 
turn off the switch on the damaged circuit until the trouble has been located. If the 
trouble is in a particular lamp socket, disconnect the attachment plug from this socket, 
until the trouble can be removed, and see that the removing attachment plug does not 
dangle in such a way as to make short circuits on the metal of the car. 

All Lights Burn Dim.—Usual trouble is, loose or slightly grounded connections, or 
poor or corroded connections at the battery. More likely the battery simply has not had 
sufficient charging. 

Lamps Too Bright.—Regulator evidently set for a higher voltage. Use lamps of 
higher voltage. 

Lamps Burn Out Often, due either to a poor grade of lamps or lamps used are not 
of proper Voltage. 

Lamps Flicker and Ammeter Unsteady.—Loose connections in light wires. Loose 
connections between battery and dynamo. Loose contacts at lamp bulbs, expose wires 
touching frames intermittently causing short circuits. 

Lamps Burn Very Dimly When Starting Pedal is Used.—Battery very weak, almost 




82 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


discharged, battery injured, probably one or more cells, due to lack of water. Battery 
terminals not rigidly connected. Lamps become dim when engine stops. This indicate* 
a discharged battery. If possible, have battery charged at once from an outside source. 
If the lights grow dim when the car is speeded up, the wires are reversed at the 
dynamo. Lamps will not light but starter cranks engine, lamps burn out, or filaments 
broken. System short circuited or open circuited at fuse or switch. 

Now in order to locate trouble in any kind of an electric system, it must be 
thoroughly remembered that it is absolutely necessary to always HAVE A COMPLETE 
CIRCUIT, AND THAT A CURRENT OF ELECTRICITY MUST ALWAYS RETURN 
TO ITS STARTING POINT; therefore( if its path becomes broken, it-absolutely cannot 
work; and, remember further, THAT A CURRENT OF ELECTRICITY ALWAYS 
TAKES THE PATH OF LEAST RESISTANCE, and if it can possibly get back home 
without performing the duty required of it, it will doso; and by keeping these facts con¬ 
stantly in mind when searching for trouble they will assist you greatly in locating it. 


CHAPTER 44. THE ELECTRICAL GEAR SHIFT—HOW IT WORKS. 



K PUSH-BUTTONS ORE 

MOUNTED UNDER 
OPERATING STEERING WHEEL 
V.EVER f, - - ■ = 


connecting 

ROD 


Ory Battery 

Pig, 4. Principle of * 
solenoid. 


—Represents travel provided torciuteh slippage, ana possible 
-prow oi clutch pedal for coasting 

O D-t—Represents travel durmj.* neutralizing and shifting 0-c. 
engagement ol master switch-) 

K-XX—Represents travel while neutralizing 
XX-V—Represents travel while engaging (he master 


WTCH '. 


c =f 

' ■ ( A-*--™" |C 

‘ r ' FV >ce I 


■-r.-H 1 

6 ) 

o 

"'..I 

— * ■;/ 


Sh-3- ' 



A— gent shift housing 
B-1-2-3-4—coils. 

C-l-2—magnet cores. 

E-E—cam shafts 
I’F— nea i r a J i z i n g 
cams 

6—ratchet’' pawl lever 
1—rocker arm. 

J —operating shafts 
H .—operating lever 
L—p a w l o.peraung 
master 6Witch 
M—master switch. 

N—locking shaft 
0—master switch re 
turn spring 

P —neotralizing return 
spring 

Z—aeutralizing return 
spring shaft, 

J> i 3kg . 106 -The 


Magnetic Gear Shift, 


The Principle.—If you press the switch button on as shown in diagram 106, figure 2, . 
you close the circuit of the solenoid number 1, causing the shaft, A, to move to the 
left. If you press button number 2, you energize solenoid number 2, causing the shaft, 
A, to move to the right. If you press button number 3, you energize solenoid number 3, 
causing shaft, B, to move to the left. If you press the button, R, energizing spool, R, 
you bring the reverse gear into mesh, pressing N, neutral button and throwing out the 
clutch, neutralizes the gears. Pressing a push button does not energize one of the 
solenoids; it merely practically closes the circuit to a certain solenoid, but the circuit 
is not completely closed until you throw the clutch pedal down to the floor board. The 









































MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


83 


clutch pedal is so arranged that you can throw out the clutch in the usual manner, by 
partially depressing the pedal, but if you push the pedal to the extreme position you 
bring the switch, N, figure 3, in contact for an instant and permit the electricity to flow 
to the particular solenoid which was selected when you pressed one of the push buttons. 
The push buttons are therefore known as selector switches, because thy do not actually 
close the circuit, but select in advance the circuit that will be energized, when you push 
the clutch pedal to the extreme position, thereby closing switch M. 

A twelve-volt battery is used. It is stated an 80-hour ampere battery will operate 
the gear shift from 390 to 491 times. 

Gear Changes.—First speed. To start forward in first speed, push selector switch 
button number 1 down until it catches, then push clutch pedal down as far as it will go, 
and the first speed gear will instantly mesh, allowing the clutch pedal to return gently, 
the clutch will engage and the car move forward in first speed. 

Second speed. Press button number 2 until it catches, and as soon as it is desired to 
shift the gears from first to second, depress the clutch as before, to its extreme position. 
This brings the second speed gear into mesh; engage the clutch. 

Third speed, press button number 3 until it catches; depress the clutch to its extreme 
position, allow clutch to return to engagements. 

Dropping Back.—In dropping back from one gear to another, the operation is the 
same, press the button corresponding to the gear wanted, and when it is desired to shift 
simply push the clutch to the extreme limits and the gears will automatically change. 

Selections.—Should button number 2 be depressed and should'it then be decided that 
number 1 is wanted, all that is necessary is to press number 1 button. This auto¬ 
matically kills number 2. Similarly any button that is down is killed by pushing any 
other button. The gears may be selected in any order desired, for example, 1 to 3, 3 to 1. 
It is not necessary to press the buttons in numerical order. 

Pre-Selections.—Speed changes may be prepared for at any time in advance of the 
actual shift by pressing the button corresponding to the gear into which it is next 
desired to fit. When the car is stopped, the gear should always be neutralized before 
the driver leaves his seat, so that when the motor is again started none of the gears 
will be in mesh. 

Neutralizing.—To throw the gears to neutral, press the end button in figure 2, and 
then depress the clutch pedal to the limit. The neutral button has no catch and does 
not remain down when it is depressed. Its function is simply to throw out the other 
buttons in order to break the electrical connections. 

Coasting.—The clutch pedal may be thrown out far enough to free the clutch without 
neutralizing or shifting the gears. The shift takes place only when the pedal is thrown 
to the extreme position. This arrangement permits disengaging the clutch so the car 
can coast. 

The Principle of a Solenoid.—This is illustrated very clearly by figure 4, diagram 
106, by touching the end of the wire to the battery terminal, which completes a current, 
around the spool of wire forming the solenoid, creates a magnetic attraction which, if 
a nail is started in the spool, will be sucked up. This is the principle upon which the 
magnetic gear shift operates. 



84 


MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


CHAPTER 45. THE OWEN MAGNETIC POWER TRANSMISSION SYSTEM. 

The Elementary Principle.—In diagram 107, figure 1, at A, is illustrated a magnet 
with keeper, familiar to everyone. B illustrates magnet and pedstal with hand crank 
to revolve, it. C, piece of steel on pedestal placed within magnet. On same line of 
travel. It will be apparent that as the magnet is revolved by turning the crank it will 
attract the piece of steel which will revolve quickly. 

Illustration number 2 at B is now revolved by a gasoline engine instead of hand 
cranked, taking the place of the flv wheel, and revolves at engine speed, regulated by 
the throttle, and to accurately describe it, we will not call B a revolving field, C is now 
part of propeller shaft, and to accurately describe this we will now call C an armature, 
and when it is running in high speed, C follows B because it is magnetically locked, but 
it will be noted that we ai-e driving through an air space or gap, there being no 
mechanical connections between the rear axles and the gas engine, only magnetism 
transmitting the torque of the gas engine to the rear axle. 

When arriving at a grade which is too steep to climb on high, we would now stall 
our gas engine unless we applied a form of speed reduction. 

CONTROL LEVER POSITION. 

Charging —car stationary, engine running, generator charging, starting, and lighting 
battery, seldom necessary as battery is automatically charged on high speed position 
when car is in motion. 



Diag. 107 The principle of the Magnetic Power Transmission 
System 

Starting.—Current from starting battery operates generator, as a motor for starting- 
engine. When engine has started, bring lever to neutral position as shown in figure 4, 
diagram 107. 





















































MODERN ELECTRICAL MOTOR CAR EQUIPMENT 


85 


Neutral*—Car stationary, engine running, clutch and generator circuit is open and 
motor is short circuited on a resistance. Bring lever to first position. 

First Position.—Generator producing current for lights, clutching effect, and maxi¬ 
mum current for electric motor results. The maximum difference between engine speed 
and car speed, and produces greater torque or pulling power. 

Second Position.—Clutching effect of generator increases and current supply to 
motor decreases, results, car speed increases. 

Third Position.—The clutching effect of generator further increases and trans¬ 
mitting more of the driving power. The motor does correspondingly less work, results 
in increased car speed. 

Fourth Position.—The generator continues to transmit more and more of the driving 
power. The work of the motor gradually decreases, results, car speed increases. 

Fifth Position.—Same general action. The generator carries nearly all the load 
while motor is practically idle. 

High.—On this position the generator clutching effect has increased to nearly lock¬ 
ing points, transmitting all the driving power. Motor no longer assists, but operates 
only as a generator to charge starting and lighting battery. 

Illustration number 3, 107, the conventional electric motor, D, as shown gives us 
reduction needed in the following manner. We now drive through what is in effect a 
slipping clutch, and it is apparent to us all that if it were possible to use the power that 
is lost in heat through the friction of the slipping clutch in the old type, gear trans¬ 
mission cars, all the power of the engine would be transmitted to the rear wheels, and 
there would he no use for a gear box. The magnetic transmission gives us this result, 
as we now find that C is trying to keep up with B, but as B and C now have ceased to 
be magnetically locked because we have changed the position of the control lever on the 
steering wheel, and therefore slipping, the difference in their relative speeds generate 
electricity which is led to D. Armature, E, being of the same form as C, and on the same 
propeller shaft, takes the electricity generated by the slip and acts as a power booster 
on the propeller shaft giving us innumerable speed reduction, wonderful flexibility, and 
absolute silence at all speeds. 





' 

, ■ ■ >. 



















_ 

. 
























. 







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# 

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